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CentOS 7.0 - man page for net::ssleay (centos section 3)

Net::SSLeay(3)		       User Contributed Perl Documentation		   Net::SSLeay(3)

NAME
       Net::SSLeay - Perl extension for using OpenSSL

SYNOPSIS
	 use Net::SSLeay qw(get_https post_https sslcat make_headers make_form);

	 ($page) = get_https('www.bacus.pt', 443, '/'); 		# Case 1

	 ($page, $response, %reply_headers)
		= get_https('www.bacus.pt', 443, '/',			# Case 2
		       make_headers(User-Agent => 'Cryptozilla/5.0b1',
				    Referer    => 'https://www.bacus.pt'
		       ));

	 ($page, $result, %headers) =					# Case 2b
		= get_https('www.bacus.pt', 443, '/protected.html',
		     make_headers(Authorization =>
				  'Basic ' . MIME::Base64::encode("$user:$pass",''))
		     );

	 ($page, $response, %reply_headers)
		= post_https('www.bacus.pt', 443, '/foo.cgi', '',	# Case 3
		       make_form(OK   => '1',
				 name => 'Sampo'
		       ));

	 $reply = sslcat($host, $port, $request);			# Case 4

	 ($reply, $err, $server_cert) = sslcat($host, $port, $request); # Case 5

	 $Net::SSLeay::trace = 2;  # 0=no debugging, 1=ciphers, 2=trace, 3=dump data

	 Net::SSLeay::initialize(); # Initialize ssl library once

DESCRIPTION
       Net::SSLeay module contains perl bindings to openssl (<http://www.openssl.org>) library.

       COMPATIBILITY NOTE: Net::SSLeay cannot be built with pre-0.9.3 openssl. It is strongly
       recommended to use at least 0.9.7 (as older versions are not tested during development).
       Some low level API functions may be available with certain openssl versions.

       Net::SSLeay module basically comprise of:

       o   High level functions for accessing web servers (by using HTTP/HTTPS)

       o   Low level API (mostly mapped 1:1 to openssl's C functions)

       o   Convenience functions (related to low level API but with more perl friendly interface)

       There is also a related module called Net::SSLeay::Handle included in this distribution
       that you might want to use instead. It has its own pod documentation.

   High level functions for accessing web servers
       This module offers some high level convenience functions for accessing web pages on SSL
       servers (for symmetry, the same API is offered for accessing http servers, too), an
       "sslcat()" function for writing your own clients, and finally access to the SSL api of the
       SSLeay/OpenSSL package so you can write servers or clients for more complicated
       applications.

       For high level functions it is most convenient to import them into your main namespace as
       indicated in the synopsis.

       Basic set of functions

       o   get_https

       o   post_https

       o   put_https

       o   head_https

       o   do_https

       o   sslcat

       o   https_cat

       o   make_form

       o   make_headers

       Case 1 (in SYNOPSIS) demonstrates the typical invocation of get_https() to fetch an HTML
       page from secure server. The first argument provides the hostname or IP in dotted decimal
       notation of the remote server to contact. The second argument is the TCP port at the
       remote end (your own port is picked arbitrarily from high numbered ports as usual for
       TCP). The third argument is the URL of the page without the host name part. If in doubt
       consult the HTTP specifications at <http://www.w3c.org>.

       Case 2 (in SYNOPSIS) demonstrates full fledged use of "get_https()". As can be seen,
       "get_https()" parses the response and response headers and returns them as a list, which
       can be captured in a hash for later reference. Also a fourth argument to "get_https()" is
       used to insert some additional headers in the request. "make_headers()" is a function that
       will convert a list or hash to such headers. By default "get_https()" supplies "Host" (to
       make virtual hosting easy) and "Accept" (reportedly needed by IIS) headers.

       Case 2b (in SYNOPSIS) demonstrates how to get a password protected page. Refer to the HTTP
       protocol specifications for further details (e.g. RFC-2617).

       Case 3 (in SYNOPSIS) invokes "post_https()" to submit a HTML/CGI form to a secure server.
       The first four arguments are equal to "get_https()" (note that the empty string ('') is
       passed as header argument).  The fifth argument is the contents of the form formatted
       according to CGI specification.	Do not post UTF-8 data as content: use utf8::downgrade
       first. In this case the helper function "make_https()" is used to do the formatting, but
       you could pass any string. "post_https()" automatically adds "Content-Type" and
       "Content-Length" headers to the request.

       Case 4 (in SYNOPSIS) shows the fundamental "sslcat()" function (inspired in spirit by the
       "netcat" utility :-). It's your swiss army knife that allows you to easily contact
       servers, send some data, and then get the response. You are responsible for formatting the
       data and parsing the response - "sslcat()" is just a transport.

       Case 5 (in SYNOPSIS) is a full invocation of "sslcat()" which allows the return of errors
       as well as the server (peer) certificate.

       The $trace global variable can be used to control the verbosity of the high level
       functions. Level 0 guarantees silence, level 1 (the default) only emits error messages.

       Alternate versions of high-level API

       o   get_https3

       o   post_https3

       o   put_https3

       o   get_https4

       o   post_https4

       o   put_https4

       The above mentioned functions actually return the response headers as a list, which only
       gets converted to hash upon assignment (this assignment looses information if the same
       header occurs twice, as may be the case with cookies). There are also other variants of
       the functions that return unprocessed headers and that return a reference to a hash.

	 ($page, $response, @headers) = get_https('www.bacus.pt', 443, '/');
	 for ($i = 0; $i < $#headers; $i+=2) {
	     print "$headers[$i] = " . $headers[$i+1] . "\n";
	 }

	 ($page, $response, $headers, $server_cert)
	   = get_https3('www.bacus.pt', 443, '/');
	 print "$headers\n";

	 ($page, $response, $headers_ref)
	   = get_https4('www.bacus.pt', 443, '/');
	 for $k (sort keys %{$headers_ref}) {
	     for $v (@{$$headers_ref{$k}}) {
		 print "$k = $v\n";
	     }
	 }

       All of the above code fragments accomplish the same thing: display all values of all
       headers. The API functions ending in "3" return the headers simply as a scalar string and
       it is up to the application to split them up. The functions ending in "4" return a
       reference to a hash of arrays (see perlref and perllol if you are not familiar with
       complex perl data structures). To access a single value of such a header hash you would do
       something like

	 print $$headers_ref{COOKIE}[0];

       Variants 3 and 4 also allow you to discover the server certificate in case you would like
       to store or display it, e.g.

	 ($p, $resp, $hdrs, $server_cert) = get_https3('www.bacus.pt', 443, '/');
	 if (!defined($server_cert) || ($server_cert == 0)) {
	     warn "Subject Name: undefined, Issuer  Name: undefined";
	 } else {
	     warn 'Subject Name: '
		 . Net::SSLeay::X509_NAME_oneline(
			Net::SSLeay::X509_get_subject_name($server_cert))
		     . 'Issuer	Name: '
			 . Net::SSLeay::X509_NAME_oneline(
				Net::SSLeay::X509_get_issuer_name($server_cert));
	 }

       Beware that this method only allows after the fact verification of the certificate: by the
       time "get_https3()" has returned the https request has already been sent to the server,
       whether you decide to trust it or not. To do the verification correctly you must either
       employ the OpenSSL certificate verification framework or use the lower level API to first
       connect and verify the certificate and only then send the http data. See the
       implementation of "ds_https3()" for guidance on how to do this.

       Using client certificates

       Secure web communications are encrypted using symmetric crypto keys exchanged using
       encryption based on the certificate of the server. Therefore in all SSL connections the
       server must have a certificate. This serves both to authenticate the server to the clients
       and to perform the key exchange.

       Sometimes it is necessary to authenticate the client as well. Two options are available:
       HTTP basic authentication and a client side certificate. The basic authentication over
       HTTPS is actually quite safe because HTTPS guarantees that the password will not travel in
       the clear. Never-the-less, problems like easily guessable passwords remain. The client
       certificate method involves authentication of the client at the SSL level using a
       certificate. For this to work, both the client and the server have certificates (which
       typically are different) and private keys.

       The API functions outlined above accept additional arguments that allow one to supply the
       client side certificate and key files. The format of these files is the same as used for
       server certificates and the caveat about encrypting private keys applies.

	 ($page, $result, %headers) =					# 2c
		= get_https('www.bacus.pt', 443, '/protected.html',
		     make_headers(Authorization =>
				  'Basic ' . MIME::Base64::encode("$user:$pass",'')),
		     '', $mime_type6, $path_to_crt7, $path_to_key8);

	 ($page, $response, %reply_headers)
		= post_https('www.bacus.pt', 443, '/foo.cgi',		# 3b
		     make_headers('Authorization' =>
				  'Basic ' . MIME::Base64::encode("$user:$pass",'')),
		     make_form(OK   => '1', name => 'Sampo'),
		     $mime_type6, $path_to_crt7, $path_to_key8);

       Case 2c (in SYNOPSIS) demonstrates getting a password protected page that also requires a
       client certificate, i.e. it is possible to use both authentication methods simultaneously.

       Case 3b (in SYNOPSIS) is a full blown POST to a secure server that requires both password
       authentication and a client certificate, just like in case 2c.

       Note: The client will not send a certificate unless the server requests one.  This is
       typically achieved by setting the verify mode to "VERIFY_PEER" on the server:

	 Net::SSLeay::set_verify(ssl, Net::SSLeay::VERIFY_PEER, 0);

       See "perldoc ~openssl/doc/ssl/SSL_CTX_set_verify.pod" for a full description.

       Working through a web proxy

       o   set_proxy

       "Net::SSLeay" can use a web proxy to make its connections. You need to first set the proxy
       host and port using "set_proxy()" and then just use the normal API functions, e.g:

	 Net::SSLeay::set_proxy('gateway.myorg.com', 8080);
	 ($page) = get_https('www.bacus.pt', 443, '/');

       If your proxy requires authentication, you can supply a username and password as well

	 Net::SSLeay::set_proxy('gateway.myorg.com', 8080, 'joe', 'salainen');
	 ($page, $result, %headers) =
		= get_https('www.bacus.pt', 443, '/protected.html',
		     make_headers(Authorization =>
				  'Basic ' . MIME::Base64::encode("susie:pass",''))
		     );

       This example demonstrates the case where we authenticate to the proxy as "joe" and to the
       final web server as "susie". Proxy authentication requires the "MIME::Base64" module to
       work.

       HTTP (without S) API

       o   get_http

       o   post_http

       o   tcpcat

       o   get_httpx

       o   post_httpx

       o   tcpxcat

       Over the years it has become clear that it would be convenient to use the light-weight
       flavour API of "Net::SSLeay" for normal HTTP as well (see "LWP" for the heavy-weight
       object-oriented approach). In fact it would be nice to be able to flip https on and off on
       the fly. Thus regular HTTP support was evolved.

	 use Net::SSLeay qw(get_http post_http tcpcat
			     get_httpx post_httpx tcpxcat
			     make_headers make_form);

	 ($page, $result, %headers)
		= get_http('www.bacus.pt', 443, '/protected.html',
		     make_headers(Authorization =>
				  'Basic ' . MIME::Base64::encode("$user:$pass",''))
		     );

	 ($page, $response, %reply_headers)
		= post_http('www.bacus.pt', 443, '/foo.cgi', '',
		       make_form(OK   => '1',
				 name => 'Sampo'
		       ));

	 ($reply, $err) = tcpcat($host, $port, $request);

	 ($page, $result, %headers)
		= get_httpx($usessl, 'www.bacus.pt', 443, '/protected.html',
		     make_headers(Authorization =>
				  'Basic ' . MIME::Base64::encode("$user:$pass",''))
		     );

	 ($page, $response, %reply_headers)
		= post_httpx($usessl, 'www.bacus.pt', 443, '/foo.cgi', '',
		       make_form(OK   => '1',  name => 'Sampo' ));

	 ($reply, $err, $server_cert) = tcpxcat($usessl, $host, $port, $request);

       As can be seen, the "x" family of APIs takes as the first argument a flag which indicates
       whether SSL is used or not.

   Certificate verification and Certificate Revocation Lists (CRLs)
       OpenSSL supports the ability to verify peer certificates. It can also optionally check the
       peer certificate against a Certificate Revocation List (CRL) from the certificates issuer.
       A CRL is a file, created by the certificate issuer that lists all the certificates that it
       previously signed, but which it now revokes. CRLs are in PEM format.

       You can enable "Net::SSLeay CRL" checking like this:

		   &Net::SSLeay::X509_STORE_set_flags
		       (&Net::SSLeay::CTX_get_cert_store($ssl),
			&Net::SSLeay::X509_V_FLAG_CRL_CHECK);

       After setting this flag, if OpenSSL checks a peer's certificate, then it will attempt to
       find a CRL for the issuer. It does this by looking for a specially named file in the
       search directory specified by CTX_load_verify_locations.  CRL files are named with the
       hash of the issuer's subject name, followed by ".r0", ".r1" etc.  For example
       "ab1331b2.r0", "ab1331b2.r1". It will read all the .r files for the issuer, and then check
       for a revocation of the peer certificate in all of them.  (You can also force it to look
       in a specific named CRL file., see below).  You can find out the hash of the issuer
       subject name in a CRL with

	       openssl crl -in crl.pem -hash -noout

       If the peer certificate does not pass the revocation list, or if no CRL is found, then the
       handshaking fails with an error.

       You can also force OpenSSL to look for CRLs in one or more arbitrarily named files.

	   my $bio = Net::SSLeay::BIO_new_file($crlfilename, 'r');
	   my $crl = Net::SSLeay::PEM_read_bio_X509_CRL($bio);
	   if ($crl) {
	       Net::SSLeay::X509_STORE_add_crl(
		    Net::SSLeay::CTX_get_cert_store($ssl, $crl)
	       );
	   } else {
	       error reading CRL....
	   }

   Using Net::SSLeay in multi-threaded applications
       IMPORTANT: versions 1.42 or earlier are not thread-safe!

       Net::SSLeay module implements all necessary stuff to be ready for multi-threaded
       environment - it requires openssl-0.9.7 or newer. The implementation fully follows thread
       safety related requirements of openssl library(see
       <http://www.openssl.org/docs/crypto/threads.html>).

       If you are about to use Net::SSLeay (or any other module based on Net::SSLeay) in multi-
       threaded perl application it is recommended to follow this best-practice:

       Initialization

       Load and initialize Net::SSLeay module in the main thread:

	   use threads;
	   use Net::SSLeay;

	   Net::SSLeay::load_error_strings();
	   Net::SSLeay::SSLeay_add_ssl_algorithms();
	   Net::SSLeay::randomize();

	   sub do_master_job {
	     #... call whatever from Net::SSLeay
	   }

	   sub do_worker_job {
	     #... call whatever from Net::SSLeay
	   }

	   #start threads
	   my $master  = threads->new(\&do_master_job, 'param1', 'param2');
	   my @workers = threads->new(\&do_worker_job, 'arg1', 'arg2') for (1..10);

	   #waiting for all threads to finish
	   $_->join() for (threads->list);

       NOTE: Openssl's "int SSL_library_init(void)" function (which is also aliased as
       "SSLeay_add_ssl_algorithms", "OpenSSL_add_ssl_algorithms" and "add_ssl_algorithms") is not
       re-entrant and multiple calls can cause a crash in threaded application.  Net::SSLeay
       implements flags preventing repeated calls to this function, therefore even multiple
       initialization via Net::SSLeay::SSLeay_add_ssl_algorithms() should work without trouble.

       Using callbacks

       Do not use callbacks across threads (the module blocks cross-thread callback operations
       and throws a warning). Allways do the callback setup, callback use and callback
       destruction within the same thread.

       Using openssl elements

       All openssl elements (X509, SSL_CTX, ...) can be directly passed between threads.

	   use threads;
	   use Net::SSLeay;

	   Net::SSLeay::load_error_strings();
	   Net::SSLeay::SSLeay_add_ssl_algorithms();
	   Net::SSLeay::randomize();

	   sub do_job {
	     my $context = shift;
	     Net::SSLeay::CTX_set_default_passwd_cb($context, sub { "secret" });
	     #...
	   }

	   my $c = Net::SSLeay::CTX_new();
	   threads->create(\&do_job, $c);

       Or:

	   use threads;
	   use Net::SSLeay;

	   my $context; #does not need to be 'shared'

	   Net::SSLeay::load_error_strings();
	   Net::SSLeay::SSLeay_add_ssl_algorithms();
	   Net::SSLeay::randomize();

	   sub do_job {
	     Net::SSLeay::CTX_set_default_passwd_cb($context, sub { "secret" });
	     #...
	   }

	   $context = Net::SSLeay::CTX_new();
	   threads->create(\&do_job);

       Using other perl modules based on Net::SSLeay

       It should be fine to use any other module based on Net::SSLeay (like IO::Socket::SSL) in
       multi-threaded applications. It is generally recommended to do any global initialization
       of such a module in the main thread before calling "threads->new(..)" or
       "threads->create(..)" but it might differ module by module.

       To be play safe you can load and init Net::SSLeay explicitly in the main thread:

	   use Net::SSLeay;
	   use Other::SSLeay::Based::Module;

	   Net::SSLeay::load_error_strings();
	   Net::SSLeay::SSLeay_add_ssl_algorithms();
	   Net::SSLeay::randomize();Net::SSLeay::initialize();
	   Net::SSLeay::initialize();

       Or even safer:

	   use Net::SSLeay;
	   use Other::SSLeay::Based::Module;

	   BEGIN {
	     Net::SSLeay::load_error_strings();
	     Net::SSLeay::SSLeay_add_ssl_algorithms();
	     Net::SSLeay::randomize();Net::SSLeay::initialize();
	   }

       Combining Net::SSLeay with other modules linked with openssl

       BEWARE: This might be a big trouble! This is not guaranteed be thread-safe!

       There are many other (XS) modules linked directly to openssl library (like Crypt::SSLeay).

       As it is expected that also "another" module will call "SSLeay_add_ssl_algorithms" at some
       point we have again a trouble with multiple openssl initialization by Net::SSLeay and
       "another" module.

       As you can expect Net::SSLeay is not able to avoid multiple initialization of openssl
       library called by "another" module, thus you have to handle this on your own (in some
       cases it might not be possible at all to avoid this).

       Threading with get_https and friends

       The convenience functions get_https, post_https etc all initialize the SSL library by
       calling Net::SSLeay::initialize which does the conventional library initialization:

	   Net::SSLeay::load_error_strings();
	   Net::SSLeay::SSLeay_add_ssl_algorithms();
	   Net::SSLeay::randomize();

       Net::SSLeay::initialize initializes the SSL library at most once.  You can override the
       Net::SSLeay::initialize function if you desire some other type of initialization behaviour
       by get_https and friends.  You can call Net::SSLeay::initialize from your own code if you
       desire this conventional library initialization.

   Convenience routines
       To be used with Low level API

	   Net::SSLeay::randomize($rn_seed_file,$additional_seed);
	   Net::SSLeay::set_cert_and_key($ctx, $cert_path, $key_path);
	   $cert = Net::SSLeay::dump_peer_certificate($ssl);
	   Net::SSLeay::ssl_write_all($ssl, $message) or die "ssl write failure";
	   $got = Net::SSLeay::ssl_read_all($ssl) or die "ssl read failure";

	   $got = Net::SSLeay::ssl_read_CRLF($ssl [, $max_length]);
	   $got = Net::SSLeay::ssl_read_until($ssl [, $delimit [, $max_length]]);
	   Net::SSLeay::ssl_write_CRLF($ssl, $message);

       o   randomize

	   seeds the openssl PRNG with "/dev/urandom" (see the top of "SSLeay.pm" for how to
	   change or configure this) and optionally with user provided data. It is very important
	   to properly seed your random numbers, so do not forget to call this. The high level
	   API functions automatically call "randomize()" so it is not needed with them. See also
	   caveats.

       o   set_cert_and_key

	   takes two file names as arguments and sets the certificate and private key to those.
	   This can be used to set either server certificates or client certificates.

       o   dump_peer_certificate

	   allows you to get a plaintext description of the certificate the peer (usually the
	   server) presented to us.

       o   ssl_read_all

	   see ssl_write_all (below)

       o   ssl_write_all

	   "ssl_read_all()" and "ssl_write_all()" provide true blocking semantics for these
	   operations (see limitation, below, for explanation). These are much preferred to the
	   low level API equivalents (which implement BSD blocking semantics). The message
	   argument to "ssl_write_all()" can be a reference. This is helpful to avoid unnecessary
	   copying when writing something big, e.g:

	       $data = 'A' x 1000000000;
	       Net::SSLeay::ssl_write_all($ssl, \$data) or die "ssl write failed";

       o   ssl_read_CRLF

	   uses "ssl_read_all()" to read in a line terminated with a carriage return followed by
	   a linefeed (CRLF).  The CRLF is included in the returned scalar.

       o   ssl_read_until

	   uses "ssl_read_all()" to read from the SSL input stream until it encounters a
	   programmer specified delimiter.  If the delimiter is undefined, $/ is used.	If $/ is
	   undefined, "\n" is used.  One can optionally set a maximum length of bytes to read
	   from the SSL input stream.

       o   ssl_write_CRLF

	   writes $message and appends CRLF to the SSL output stream.

   Initialization
       In order to use the low level API you should start your programs with the following
       incantation:

	       use Net::SSLeay qw(die_now die_if_ssl_error);
	       Net::SSLeay::load_error_strings();
	       Net::SSLeay::SSLeay_add_ssl_algorithms();    # Important!
	       Net::SSLeay::ENGINE_load_builtin_engines();  # If you want built-in engines
	       Net::SSLeay::ENGINE_register_all_complete(); # If you want built-in engines
	       Net::SSLeay::randomize();

   Error handling functions
       I can not emphasize the need to check for error enough. Use these functions even in the
       most simple programs, they will reduce debugging time greatly. Do not ask questions on the
       mailing list without having first sprinkled these in your code.

       o   die_now

       o   die_if_ssl_error

	   "die_now()" and "die_if_ssl_error()" are used to conveniently print the SSLeay error
	   stack when something goes wrong:

		   Net::SSLeay::connect($ssl) or die_now("Failed SSL connect ($!)");

		   Net::SSLeay::write($ssl, "foo") or die_if_ssl_error("SSL write ($!)");

       o   print_errs

	   You can also use "Net::SSLeay::print_errs()" to dump the error stack without exiting
	   the program. As can be seen, your code becomes much more readable if you import the
	   error reporting functions into your main name space.

   Sockets
       Perl uses file handles for all I/O. While SSLeay has a quite flexible BIO mechanism and
       perl has an evolved PerlIO mechanism, this module still sticks to using file descriptors.
       Thus to attach SSLeay to a socket you should use "fileno()" to extract the underlying file
       descriptor:

	   Net::SSLeay::set_fd($ssl, fileno(S));   # Must use fileno

       You should also set $| to 1 to eliminate STDIO buffering so you do not get confused if you
       use perl I/O functions to manipulate your socket handle.

       If you need to select(2) on the socket, go right ahead, but be warned that OpenSSL does
       some internal buffering so SSL_read does not always return data even if the socket
       selected for reading (just keep on selecting and trying to read). "Net::SSLeay" is no
       different from the C language OpenSSL in this respect.

   Callbacks
       You can establish a per-context verify callback function something like this:

	       sub verify {
		   my ($ok, $x509_store_ctx) = @_;
		   print "Verifying certificate...\n";
		       ...
		   return $ok;
	       }

       It is used like this:

	       Net::SSLeay::set_verify ($ssl, Net::SSLeay::VERIFY_PEER, \&verify);

       Per-context callbacks for decrypting private keys are implemented.

	       Net::SSLeay::CTX_set_default_passwd_cb($ctx, sub { "top-secret" });
	       Net::SSLeay::CTX_use_PrivateKey_file($ctx, "key.pem",
						    Net::SSLeay::FILETYPE_PEM)
		   or die "Error reading private key";
	       Net::SSLeay::CTX_set_default_passwd_cb($ctx, undef);

       If Hello Extensions are supported by your OpenSSL, a session secret callback can be set up
       to be called when a session secret is set by openssl.

       Establish it like this:
	   Net::SSLeay::set_session_secret_cb($ssl, \&session_secret_cb, $somedata);

       It will be called like this:

	   sub session_secret_cb
	   {
	       my ($secret, \@cipherlist, \$preferredcipher, $somedata) = @_;
	   }

       No other callbacks are implemented. You do not need to use any callback for simple (i.e.
       normal) cases where the SSLeay built-in verify mechanism satisfies your needs.

       It is required to reset these callbacks to undef immediately after use to prevent memory
       leaks, thread safety problems and crashes on exit that can occur if different threads set
       different callbacks.

       If you want to use callback stuff, see examples/callback.pl! It's the only one I am able
       to make work reliably.

   Low level API
       In addition to the high level functions outlined above, this module contains straight-
       forward access to CRYPTO and SSL parts of OpenSSL C API.

       See the "*.h" headers from OpenSSL C distribution for a list of low level SSLeay functions
       to call (check SSLeay.xs to see if some function has been implemented). The module strips
       the initial "SSL_" off of the SSLeay names.  Generally you should use "Net::SSLeay::" in
       its place.

       Note that some functions are prefixed with "P_" - these are very close to the original API
       however contain some kind of a wrapper making its interface more perl friendly.

       For example:

       In C:

	       #include <ssl.h>

	       err = SSL_set_verify (ssl, SSL_VERIFY_CLIENT_ONCE,
					  &your_call_back_here);

       In Perl:

	       use Net::SSLeay;

	       $err = Net::SSLeay::set_verify ($ssl,
					       Net::SSLeay::VERIFY_CLIENT_ONCE,
					       \&your_call_back_here);

       If the function does not start with "SSL_" you should use the full function name, e.g.:

	       $err = Net::SSLeay::ERR_get_error;

       The following new functions behave in perlish way:

	       $got = Net::SSLeay::read($ssl);
					   # Performs SSL_read, but returns $got
					   # resized according to data received.
					   # Returns undef on failure.

	       Net::SSLeay::write($ssl, $foo) || die;
					   # Performs SSL_write, but automatically
					   # figures out the size of $foo

       Low level API: Version related functions

       o   SSLeay

	   COMPATIBILITY: not available in Net-SSLeay-1.42 and before

	   Gives version number (numeric) of underlaying openssl library.

	    my $ver_number = Net::SSLeay::SSLeay();
	    # returns: the number identifying the openssl release
	    #
	    # 0x00903100 => openssl-0.9.3
	    # 0x00904100 => openssl-0.9.4
	    # 0x00905100 => openssl-0.9.5
	    # 0x0090600f => openssl-0.9.6
	    # 0x0090601f => openssl-0.9.6a
	    # 0x0090602f => openssl-0.9.6b
	    # ...
	    # 0x009060df => openssl-0.9.6m
	    # 0x0090700f => openssl-0.9.7
	    # 0x0090701f => openssl-0.9.7a
	    # 0x0090702f => openssl-0.9.7b
	    # ...
	    # 0x009070df => openssl-0.9.7m
	    # 0x0090800f => openssl-0.9.8
	    # 0x0090801f => openssl-0.9.8a
	    # 0x0090802f => openssl-0.9.8b
	    # ...
	    # 0x0090814f => openssl-0.9.8t
	    # 0x1000000f => openssl-1.0.0
	    # 0x1000004f => openssl-1.0.0d
	    # 0x1000007f => openssl-1.0.0g

	   You can use it like this:

	     if (Net::SSLeay::SSLeay() < 0x0090800f) {
	       die "you need openssl-0.9.8 or higher";
	     }

       o   SSLeay_version

	   COMPATIBILITY: not available in Net-SSLeay-1.42 and before

	   Gives version number (string) of underlaying openssl library.

	    my $ver_string = Net::SSLeay::SSLeay_version($type);
	    # $type
	    #	0 (=SSLEAY_VERSION) - e.g. 'OpenSSL 1.0.0d 8 Feb 2011'
	    #	2 (=SSLEAY_CFLAGS)  - e.g. 'compiler: gcc -D_WINDLL -DOPENSSL_USE_APPLINK .....'
	    #	3 (=SSLEAY_BUILT_ON)- e.g. 'built on: Fri May  6 00:00:46 GMT 2011'
	    #	4 (=SSLEAY_PLATFORM)- e.g. 'platform: mingw'
	    #
	    # returns: string

	    Net::SSLeay::SSLeay_version();
	    #is equivalent to
	    Net::SSLeay::SSLeay_version(0);

	   Check openssl doc <http://www.openssl.org/docs/crypto/SSLeay_version.html>

       Low level API: Initialization related functions

       o   library_init

	   Initialize SSL library by registering algorithms.

	    my $rv = Net::SSLeay::library_init();
	    #
	    # returns: always 1

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_library_init.html>

       o   add_ssl_algorithms

	   The alias for "library_init"

	    Net::SSLeay::add_ssl_algorithms();

       o   OpenSSL_add_ssl_algorithms

	   The alias for "library_init"

	    Net::SSLeay::OpenSSL_add_ssl_algorithms();

       o   SSLeay_add_ssl_algorithms

	   The alias for "library_init"

	    Net::SSLeay::SSLeay_add_ssl_algorithms();

       o   load_error_strings

	   Registers the error strings for all libcrypto + libssl related functions.

	    Net::SSLeay::load_error_strings();
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/crypto/ERR_load_crypto_strings.html>

       o   ERR_load_crypto_strings

	   Registers the error strings for all libcrypto functions. No need to call this function
	   if you have already called "load_error_strings".

	    Net::SSLeay::ERR_load_crypto_strings();
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/crypto/ERR_load_crypto_strings.html>

       o   ERR_load_RAND_strings

	   Registers the error strings for RAND related functions. No need to call this function
	   if you have already called "load_error_strings".

	    Net::SSLeay::ERR_load_RAND_strings();
	    #
	    # returns: no return value

       o   ERR_load_SSL_strings

	   Registers the error strings for SSL related functions. No need to call this function
	   if you have already called "load_error_strings".

	    Net::SSLeay::ERR_load_SSL_strings();
	    #
	    # returns: no return value

       o   OpenSSL_add_all_algorithms

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Add algorithms to internal table.

	    Net::SSLeay::OpenSSL_add_all_algorithms();
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/crypto/OpenSSL_add_all_algorithms.html>

       o   OPENSSL_add_all_algorithms_conf

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Similar to "OpenSSL_add_all_algorithms" - will ALWAYS load the config file

	    Net::SSLeay::OPENSSL_add_all_algorithms_conf();
	    #
	    # returns: no return value

       o   OPENSSL_add_all_algorithms_noconf

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Similar to "OpenSSL_add_all_algorithms" - will NEVER load the config file

	    Net::SSLeay::OPENSSL_add_all_algorithms_noconf();
	    #
	    # returns: no return value

       Low level API: ERR_* and SSL_alert_* related functions

       NOTE: Please note that SSL_alert_* function have "SSL_" part stripped from their names.

       o   ERR_clear_error

	   Clear the error queue.

	    Net::SSLeay::ERR_clear_error();
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/crypto/ERR_clear_error.html>

       o   ERR_error_string

	   Generates a human-readable string representing the error code $error.

	    my $rv = Net::SSLeay::ERR_error_string($error);
	    # $error - (unsigned integer) error code
	    #
	    # returns: string

	   Check openssl doc <http://www.openssl.org/docs/crypto/ERR_error_string.html>

       o   ERR_get_error

	   Returns the earliest error code from the thread's error queue and removes the entry.
	   This function can be called repeatedly until there are no more error codes to return.

	    my $rv = Net::SSLeay::ERR_get_error();
	    #
	    # returns: (unsigned integer) error code

	   Check openssl doc <http://www.openssl.org/docs/crypto/ERR_get_error.html>

       o   ERR_peek_error

	   Returns the earliest error code from the thread's error queue without modifying it.

	    my $rv = Net::SSLeay::ERR_peek_error();
	    #
	    # returns: (unsigned integer) error code

	   Check openssl doc <http://www.openssl.org/docs/crypto/ERR_get_error.html>

       o   ERR_put_error

	   Adds an error code to the thread's error queue. It signals that the error of $reason
	   code reason occurred in function $func of library $lib, in line number $line of $file.

	    Net::SSLeay::ERR_put_error($lib, $func, $reason, $file, $line);
	    # $lib - (integer) library id (check openssl/err.h for constants e.g. ERR_LIB_SSL)
	    # $func - (integer) function id (check openssl/ssl.h for constants e.g. SSL_F_SSL23_READ)
	    # $reason - (integer) reason id (check openssl/ssl.h for constants e.g. SSL_R_SSL_HANDSHAKE_FAILURE)
	    # $file - (string) file name
	    # $line - (integer) line number in $file
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/crypto/ERR_put_error.html> and
	   <http://www.openssl.org/docs/crypto/err.html>

       o   alert_desc_string

	   Returns a two letter string as a short form describing the reason of the alert
	   specified by value.

	    my $rv = Net::SSLeay::alert_desc_string($value);
	    # $value - (integer) allert id (check openssl/ssl.h for SSL3_AD_* and TLS1_AD_* constants)
	    #
	    # returns: description string (2 letters)

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_alert_type_string.html>

       o   alert_desc_string_long

	   Returns a string describing the reason of the alert specified by value.

	    my $rv = Net::SSLeay::alert_desc_string_long($value);
	    # $value - (integer) allert id (check openssl/ssl.h for SSL3_AD_* and TLS1_AD_* constants)
	    #
	    # returns: description string

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_alert_type_string.html>

       o   alert_type_string

	   Returns a one letter string indicating the type of the alert specified by value.

	    my $rv = Net::SSLeay::alert_type_string($value);
	    # $value - (integer) allert id (check openssl/ssl.h for SSL3_AD_* and TLS1_AD_* constants)
	    #
	    # returns: string (1 letter)

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_alert_type_string.html>

       o   alert_type_string_long

	   Returns a string indicating the type of the alert specified by value.

	    my $rv = Net::SSLeay::alert_type_string_long($value);
	    # $value - (integer) allert id (check openssl/ssl.h for SSL3_AD_* and TLS1_AD_* constants)
	    #
	    # returns: string

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_alert_type_string.html>

       Low level API: SSL_METHOD_* related functions

       o   SSLv2_method

	   Returns SSL_METHOD structure corresponding to SSLv2 method, the return value can be
	   later used as a param of "CTX_new_with_method". Only available where suported by the
	   underlying openssl.

	    my $rv = Net::SSLeay::SSLv2_method();
	    #
	    # returns: value corresponding to openssl's SSL_METHOD structure (0 on failure)

       o   SSLv3_method

	   Returns SSL_METHOD structure corresponding to SSLv3 method, the return value can be
	   later used as a param of "CTX_new_with_method".

	    my $rv = Net::SSLeay::SSLv3_method();
	    #
	    # returns: value corresponding to openssl's SSL_METHOD structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_new.html>

       o   TLSv1_method

	   Returns SSL_METHOD structure corresponding to TLSv1 method, the return value can be
	   later used as a param of "CTX_new_with_method".

	    my $rv = Net::SSLeay::TLSv1_method();
	    #
	    # returns: value corresponding to openssl's SSL_METHOD structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_new.html>

       o   TLSv1_1_method

	   Returns SSL_METHOD structure corresponding to TLSv1_1 method, the return value can be
	   later used as a param of "CTX_new_with_method". Only available where supported by the
	   underlying openssl.

	    my $rv = Net::SSLeay::TLSv1__1method();
	    #
	    # returns: value corresponding to openssl's SSL_METHOD structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_new.html>

       o   TLSv1_2_method

	   Returns SSL_METHOD structure corresponding to TLSv1_2 method, the return value can be
	   later used as a param of "CTX_new_with_method". Only available where supported by the
	   underlying openssl.

	    my $rv = Net::SSLeay::TLSv1_2_method();
	    #
	    # returns: value corresponding to openssl's SSL_METHOD structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_new.html>

       Low level API: ENGINE_* related functions

       o   ENGINE_load_builtin_engines

	   Load all bundled ENGINEs into memory and make them visible.

	    Net::SSLeay::ENGINE_load_builtin_engines();
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/crypto/engine.html>

       o   ENGINE_register_all_complete

	   Register all loaded ENGINEs for every algorithm they collectively implement.

	    Net::SSLeay::ENGINE_register_all_complete();
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/crypto/engine.html>

       o   ENGINE_set_default

	   Set default engine to $e + set its flags to $flags.

	    my $rv = Net::SSLeay::ENGINE_set_default($e, $flags);
	    # $e - value corresponding to openssl's ENGINE structure
	    # $flags - (integer) engine flags
	    #	       flags value can be made by bitwise "OR"ing:
	    #	       0x0001 - ENGINE_METHOD_RSA
	    #	       0x0002 - ENGINE_METHOD_DSA
	    #	       0x0004 - ENGINE_METHOD_DH
	    #	       0x0008 - ENGINE_METHOD_RAND
	    #	       0x0010 - ENGINE_METHOD_ECDH
	    #	       0x0020 - ENGINE_METHOD_ECDSA
	    #	       0x0040 - ENGINE_METHOD_CIPHERS
	    #	       0x0080 - ENGINE_METHOD_DIGESTS
	    #	       0x0100 - ENGINE_METHOD_STORE
	    #	       0x0200 - ENGINE_METHOD_PKEY_METHS
	    #	       0x0400 - ENGINE_METHOD_PKEY_ASN1_METHS
	    #	       Obvious all-or-nothing cases:
	    #	       0xFFFF - ENGINE_METHOD_ALL
	    #	       0x0000 - ENGINE_METHOD_NONE
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc <http://www.openssl.org/docs/crypto/engine.html>

       o   ENGINE_by_id

	   Get ENGINE by its identification $id.

	    my $rv = Net::SSLeay::ENGINE_by_id($id);
	    # $id - (string) engine identification e.g. "dynamic"
	    #
	    # returns: value corresponding to openssl's ENGINE structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/crypto/engine.html>

       Low level API: EVP_PKEY_* related functions

       o   EVP_PKEY_copy_parameters

	   Copies the parameters from key $from to key $to.

	    my $rv = Net::SSLeay::EVP_PKEY_copy_parameters($to, $from);
	    # $to - value corresponding to openssl's EVP_PKEY structure
	    # $from - value corresponding to openssl's EVP_PKEY structure
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc <http://www.openssl.org/docs/crypto/EVP_PKEY_cmp.html>

       o   EVP_PKEY_new

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Creates a new EVP_PKEY structure.

	    my $rv = Net::SSLeay::EVP_PKEY_new();
	    #
	    # returns: value corresponding to openssl's EVP_PKEY structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/crypto/EVP_PKEY_new.html>

       o   EVP_PKEY_free

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Free an allocated EVP_PKEY structure.

	    Net::SSLeay::EVP_PKEY_free($pkey);
	    # $pkey - value corresponding to openssl's EVP_PKEY structure
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/crypto/EVP_PKEY_new.html>

       o   EVP_PKEY_assign_RSA

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Set the key referenced by $pkey to $key

	   NOTE: In accordance with the OpenSSL naming convention the $key assigned to the $pkey
	   using the "1" functions must be freed as well as $pkey.

	    my $rv = Net::SSLeay::EVP_PKEY_assign_RSA($pkey, $key);
	    # $pkey - value corresponding to openssl's EVP_PKEY structure
	    # $key - value corresponding to openssl's RSA structure
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc <http://www.openssl.org/docs/crypto/EVP_PKEY_set1_RSA.html>

       o   EVP_PKEY_bits

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Returns the size of the key $pkey in bits.

	    my $rv = Net::SSLeay::EVP_PKEY_bits($pkey);
	    # $pkey - value corresponding to openssl's EVP_PKEY structure
	    #
	    # returns: size in bits

       o   EVP_PKEY_size

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Returns the maximum size of a signature in bytes. The actual signature may be smaller.

	    my $rv = Net::SSLeay::EVP_PKEY_size($pkey);
	    # $pkey - value corresponding to openssl's EVP_PKEY structure
	    #
	    # returns: the maximum size in bytes

	   Check openssl doc <http://www.openssl.org/docs/crypto/EVP_SignInit.html>

       o   EVP_PKEY_id

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before; requires at least
	   openssl-1.0.0

	   Returns $pkey type (integer value of corresponding NID).

	    my $rv = Net::SSLeay::EVP_PKEY_id($pkey);
	    # $pkey - value corresponding to openssl's EVP_PKEY structure
	    #
	    # returns: (integer) key type

	   Example:

	    my $pubkey = Net::SSLeay::X509_get_pubkey($x509);
	    my $type = Net::SSLeay::EVP_PKEY_id($pubkey);
	    print Net::SSLeay::OBJ_nid2sn($type);	      #prints e.g. 'rsaEncryption'

       Low level API: PEM_* related functions

       Check openssl doc <http://www.openssl.org/docs/crypto/pem.html>

       o   PEM_read_bio_X509

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Loads PEM formated X509 certificate via given BIO structure.

	    my $rv = Net::SSLeay::PEM_read_bio_X509($bio);
	    # $bio - value corresponding to openssl's BIO structure
	    #
	    # returns: value corresponding to openssl's X509 structure (0 on failure)

	   Example:

	    my $bio = Net::SSLeay::BIO_new_file($filename, 'r');
	    my $x509 = Net::SSLeay::PEM_read_bio_X509($bio);
	    Net::SSLeay::BIO_free($bio);

       o   PEM_read_bio_X509_REQ

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Loads PEM formated X509_REQ object via given BIO structure.

	    my $rv = Net::SSLeay::PEM_read_bio_X509_REQ($bio, $x=NULL, $cb=NULL, $u=NULL);
	    # $bio - value corresponding to openssl's BIO structure
	    #
	    # returns: value corresponding to openssl's X509_REQ structure (0 on failure)

	   Example:

	    my $bio = Net::SSLeay::BIO_new_file($filename, 'r');
	    my $x509_req = Net::SSLeay::PEM_read_bio_X509_REQ($bio);
	    Net::SSLeay::BIO_free($bio);

       o   PEM_read_bio_DHparams

	   Reads DH structure from BIO.

	    my $rv = Net::SSLeay::PEM_read_bio_DHparams($bio);
	    # $bio - value corresponding to openssl's BIO structure
	    #
	    # returns: value corresponding to openssl's DH structure (0 on failure)

       o   PEM_read_bio_X509_CRL

	   Reads X509_CRL structure from BIO.

	    my $rv = Net::SSLeay::PEM_read_bio_X509_CRL($bio);
	    # $bio - value corresponding to openssl's BIO structure
	    #
	    # returns: value corresponding to openssl's X509_CRL structure (0 on failure)

       o   PEM_read_bio_PrivateKey

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Loads PEM formated private key via given BIO structure.

	    my $rv = Net::SSLeay::PEM_read_bio_PrivateKey($bio, $cb, $data);
	    # $bio - value corresponding to openssl's BIO structure
	    # $cb - reference to perl callback function
	    # $data - data that will be passed to callback function (see examples below)
	    #
	    # returns: value corresponding to openssl's EVP_PKEY structure (0 on failure)

	   Example:

	    my $bio = Net::SSLeay::BIO_new_file($filename, 'r');
	    my $privkey = Net::SSLeay::PEM_read_bio_PrivateKey($bio); #ask for password if needed
	    Net::SSLeay::BIO_free($bio);

	   To use password you have the following options:

	    $privkey = Net::SSLeay::PEM_read_bio_PrivateKey($bio, \&callback_func); # use callback func for getting password
	    $privkey = Net::SSLeay::PEM_read_bio_PrivateKey($bio, \&callback_func, $data); # use callback_func + pass $data to callback_func
	    $privkey = Net::SSLeay::PEM_read_bio_PrivateKey($bio, undef, "secret"); # use password "secret"
	    $privkey = Net::SSLeay::PEM_read_bio_PrivateKey($bio, undef, "");	    # use empty password

	   Callback function signature:

	    sub callback_func {
	      my ($max_passwd_size, $rwflag, $data) = @_;
	      # $max_passwd_size - maximum size of returned password (longer values will be discarded)
	      # $rwflag - indicates whether we are loading(0) or storing(1) - for PEM_read_bio_PrivateKey always 0
	      # $data - the data passed to PEM_read_bio_PrivateKey as 3rd parameter

	      return "secret";
	    }

       o   PEM_get_string_X509

	   NOTE: Does not exactly correspond to any low level API function

	   Converts/exports X509 certificate to string (PEM format).

	    Net::SSLeay::PEM_get_string_X509($x509);
	    # $x509 - value corresponding to openssl's X509 structure
	    #
	    # returns: string with $x509 in PEM format

       o   PEM_get_string_PrivateKey

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Converts public key $pk into PEM formated string (optionally protected with password).

	    my $rv = Net::SSLeay::PEM_get_string_PrivateKey($pk, $passwd, $enc_alg);
	    # $pk - value corresponding to openssl's EVP_PKEY structure
	    # $passwd - [optional] (string) password to use for key encryption
	    # $enc_alg - [optional] algorithm to use for key encryption (default: DES_CBC) - value corresponding to openssl's EVP_CIPHER structure
	    #
	    # returns: PEM formated string

	   Examples:

	    $pem_privkey = Net::SSLeay::PEM_get_string_PrivateKey($pk);
	    $pem_privkey = Net::SSLeay::PEM_get_string_PrivateKey($pk, "secret");
	    $pem_privkey = Net::SSLeay::PEM_get_string_PrivateKey($pk, "secret", Net::SSLeay::EVP_get_cipherbyname("DES-EDE3-CBC"));

       o   PEM_get_string_X509_CRL

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Converts X509_CRL object $x509_crl into PEM formated string.

	    Net::SSLeay::PEM_get_string_X509_CRL($x509_crl);
	    # $x509_crl - value corresponding to openssl's X509_CRL structure
	    #
	    # returns: no return value

       o   PEM_get_string_X509_REQ

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Converts X509_REQ object $x509_crl into PEM formated string.

	    Net::SSLeay::PEM_get_string_X509_REQ($x509_req);
	    # $x509_req - value corresponding to openssl's X509_REQ structure
	    #
	    # returns: no return value

       Low level API: d2i_* (DER format) related functions

       o   d2i_X509_bio

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Loads DER formated X509 certificate via given BIO structure.

	    my $rv = Net::SSLeay::d2i_X509_bio($bp);
	    # $bp - value corresponding to openssl's BIO structure
	    #
	    # returns: value corresponding to openssl's X509 structure (0 on failure)

	   Example:

	    my $bio = Net::SSLeay::BIO_new_file($filename, 'rb');
	    my $x509 = Net::SSLeay::d2i_X509_bio($bio);
	    Net::SSLeay::BIO_free($bio);

	   Check openssl doc <http://www.openssl.org/docs/crypto/d2i_X509.html>

       o   d2i_X509_CRL_bio

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Loads DER formated X509_CRL object via given BIO structure.

	    my $rv = Net::SSLeay::d2i_X509_CRL_bio($bp);
	    # $bp - value corresponding to openssl's BIO structure
	    #
	    # returns: value corresponding to openssl's X509_CRL structure (0 on failure)

	   Example:

	    my $bio = Net::SSLeay::BIO_new_file($filename, 'rb');
	    my $x509_crl = Net::SSLeay::d2i_X509_CRL_bio($bio);
	    Net::SSLeay::BIO_free($bio);

       o   d2i_X509_REQ_bio

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Loads DER formated X509_REQ object via given BIO structure.

	    my $rv = Net::SSLeay::d2i_X509_REQ_bio($bp);
	    # $bp - value corresponding to openssl's BIO structure
	    #
	    # returns: value corresponding to openssl's X509_REQ structure (0 on failure)

	   Example:

	    my $bio = Net::SSLeay::BIO_new_file($filename, 'rb');
	    my $x509_req = Net::SSLeay::d2i_X509_REQ_bio($bio);
	    Net::SSLeay::BIO_free($bio);

       Low level API: PKCS12 related functions

       o   P_PKCS12_load_file

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Loads X509 certificate + private key + certificates of CA chain (if present in PKCS12
	   file).

	    my ($privkey, $cert, @cachain) = Net::SSLeay::P_PKCS12_load_file($filename, $load_chain, $password);
	    # $filename - name of PKCS12 file
	    # $load_chain - [optional] whether load(1) or not(0) CA chain (default: 0)
	    # $password - [optional] password for private key
	    #
	    # returns: triplet ($privkey, $cert, @cachain)
	    #	       $privkey - value corresponding to openssl's EVP_PKEY structure
	    #	       $cert - value corresponding to openssl's X509 structure
	    #	       @cachain - array of values corresponding to openssl's X509 structure (empty if no CA chain in PKCS12)

	   IMPORTANT NOTE: after you do the job you need to call X509_free() on $privkey + all
	   members of @cachain and EVP_PKEY_free() on $privkey.

	   Examples:

	    my ($privkey, $cert) = Net::SSLeay::P_PKCS12_load_file($filename);
	    #or
	    my ($privkey, $cert) = Net::SSLeay::P_PKCS12_load_file($filename, 0, $password);
	    #or
	    my ($privkey, $cert, @cachain) = Net::SSLeay::P_PKCS12_load_file($filename, 1);
	    #or
	    my ($privkey, $cert, @cachain) = Net::SSLeay::P_PKCS12_load_file($filename, 1, $password);

	    #BEWARE: THIS IS WRONG - MEMORY LEAKS! (you cannot free @cachain items)
	    my ($privkey, $cert) = Net::SSLeay::P_PKCS12_load_file($filename, 1, $password);

       Low level API: SESSION_* related functions

       o   d2i_SSL_SESSION

	   Transforms the external ASN1 representation of an SSL/TLS session, stored as binary
	   data at location pp with length length, into an SSL_SESSION object.

	   ??? (does this function really work?)

	    my $rv = Net::SSLeay::d2i_SSL_SESSION($a, $pp, $length);
	    # $a - value corresponding to openssl's SSL_SESSION structure
	    # $pp - pointer/buffer ???
	    # $length - ???
	    #
	    # returns: ???

	   Check openssl doc <http://www.openssl.org/docs/ssl/d2i_SSL_SESSION.html>

       o   i2d_SSL_SESSION

	   Transforms the SSL_SESSION object in into the ASN1 representation and stores it into
	   the memory location pointed to by pp. The length of the resulting ASN1 representation
	   is returned.

	   ??? (does this function really work?)

	    my $rv = Net::SSLeay::i2d_SSL_SESSION($in, $pp);
	    # $in - value corresponding to openssl's SSL_SESSION structure
	    # $pp - pointer/data ???
	    #
	    # returns: 1 on success, 0

	   Check openssl doc <http://www.openssl.org/docs/ssl/d2i_SSL_SESSION.html>

       o   SESSION_new

	   Creates a new SSL_SESSION structure.

	    my $rv = Net::SSLeay::SESSION_new();
	    #
	    # returns: value corresponding to openssl's SSL_SESSION structure (0 on failure)

       o   SESSION_free

	   Free an allocated SSL_SESSION structure.

	    Net::SSLeay::SESSION_free($ses);
	    # $ses - value corresponding to openssl's SSL_SESSION structure
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_SESSION_free.html>

       o   SESSION_cmp

	   Compare two SSL_SESSION structures.

	    my $rv = Net::SSLeay::SESSION_cmp($sesa, $sesb);
	    # $sesa - value corresponding to openssl's SSL_SESSION structure
	    # $sesb - value corresponding to openssl's SSL_SESSION structure
	    #
	    # returns: 0 if the two structures are the same

	   NOTE: Not available in openssl 1.0 or later

       o   SESSION_get_app_data

	   Can be used to get application defined value/data.

	    my $rv = Net::SSLeay::SESSION_get_app_data($ses);
	    # $ses - value corresponding to openssl's SSL_SESSION structure
	    #
	    # returns: string/buffer/pointer ???

       o   SESSION_set_app_data

	   Can be used to set some application defined value/data.

	    my $rv = Net::SSLeay::SESSION_set_app_data($s, $a);
	    # $s - value corresponding to openssl's SSL_SESSION structure
	    # $a - (string/buffer/pointer ???) data
	    #
	    # returns: ???

       o   SESSION_get_ex_data

	   Is used to retrieve the information for $idx from session $ses.

	    my $rv = Net::SSLeay::SESSION_get_ex_data($ses, $idx);
	    # $ses - value corresponding to openssl's SSL_SESSION structure
	    # $idx - (integer) index for application specific data
	    #
	    # returns: pointer to ???

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_SESSION_get_ex_new_index.html>

       o   SESSION_set_ex_data

	   Is used to store application data at arg for idx into the session object.

	    my $rv = Net::SSLeay::SESSION_set_ex_data($ss, $idx, $data);
	    # $ss - value corresponding to openssl's SSL_SESSION structure
	    # $idx - (integer) ???
	    # $data - (pointer) ???
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_SESSION_get_ex_new_index.html>

       o   SESSION_get_ex_new_index

	   Is used to register a new index for application specific data.

	    my $rv = Net::SSLeay::SESSION_get_ex_new_index($argl, $argp, $new_func, $dup_func, $free_func);
	    # $argl - (long) ???
	    # $argp - (pointer) ???
	    # $new_func - function pointer ??? (CRYPTO_EX_new *)
	    # $dup_func - function pointer ??? (CRYPTO_EX_dup *)
	    # $free_func - function pointer ??? (CRYPTO_EX_free *)
	    #
	    # returns: (integer) ???

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_SESSION_get_ex_new_index.html>

       o   SESSION_get_master_key

	   NOTE: Does not exactly correspond to any low level API function

	   Returns 'master_key' value from SSL_SESSION structure $s

	    Net::SSLeay::SESSION_get_master_key($s);
	    # $s - value corresponding to openssl's SSL_SESSION structure
	    #
	    # returns: master key (binary data)

       o   SESSION_set_master_key

	   Sets 'master_key' value for SSL_SESSION structure $s

	    Net::SSLeay::SESSION_set_master_key($s, $key);
	    # $s - value corresponding to openssl's SSL_SESSION structure
	    # $key - master key (binary data)
	    #
	    # returns: no return value

       o   SESSION_get_time

	   Returns the time at which the session s was established.  The time is given in seconds
	   since 1.1.1970.

	    my $rv = Net::SSLeay::SESSION_get_time($s);
	    # $s - value corresponding to openssl's SSL_SESSION structure
	    #
	    # returns: timestamp (seconds since 1.1.1970)

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_SESSION_get_time.html>

       o   get_time

	   Technically the same functionality as "SESSION_get_time".

	    my $rv = Net::SSLeay::get_time($s);

       o   SESSION_get_timeout

	   Returns the timeout value set for session $s in seconds.

	    my $rv = Net::SSLeay::SESSION_get_timeout($s);
	    # $s - value corresponding to openssl's SSL_SESSION structure
	    #
	    # returns: timeout (in seconds)

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_SESSION_get_time.html>

       o   get_timeout

	   Technically the same functionality as "SESSION_get_timeout".

	    my $rv = Net::SSLeay::get_timeout($s);

       o   SESSION_print

	   NOTE: Does not exactly correspond to any low level API function

	   Prints session details (e.g. protocol version, ciprher, session-id ...) to BIO.

	    my $rv = Net::SSLeay::SESSION_print($fp, $ses);
	    # $fp - value corresponding to openssl's BIO structure
	    # $ses - value corresponding to openssl's SSL_SESSION structure
	    #
	    # returns: 1 on success, 0 on failure

	   You have to use necessary BIO functions like this:

	    # let us have $ssl corresponding to openssl's SSL structure
	    my $ses = Net::SSLeay::get_session($ssl);
	    my $bio = Net::SSLeay::BIO_new(&Net::SSLeay::BIO_s_mem);
	    Net::SSLeay::SESSION_print($bio, $ses);
	    print Net::SSLeay::BIO_read($bio);

       o   SESSION_print_fp

	   Prints session details (e.g. protocol version, ciprher, session-id ...) to file
	   handle.

	    my $rv = Net::SSLeay::SESSION_print_fp($fp, $ses);
	    # $fp - perl file handle
	    # $ses - value corresponding to openssl's SSL_SESSION structure
	    #
	    # returns: 1 on success, 0 on failure

	   Example:

	    # let us have $ssl corresponding to openssl's SSL structure
	    my $ses = Net::SSLeay::get_session($ssl);
	    open my $fh, ">", "output.txt";
	    Net::SSLeay::SESSION_print_fp($fh,$ses);

       o   SESSION_set_time

	   Replaces the creation time of the session s with the chosen value $t (seconds since
	   1.1.1970).

	    my $rv = Net::SSLeay::SESSION_set_time($ses, $t);
	    # $ses - value corresponding to openssl's SSL_SESSION structure
	    # $t - time value
	    #
	    # returns: 1 on success

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_SESSION_get_time.html>

       o   set_time

	   Technically the same functionality as "SESSION_set_time".

	    my $rv = Net::SSLeay::set_time($ses, $t);

       o   SESSION_set_timeout

	   Sets the timeout value for session s in seconds to $t.

	    my $rv = Net::SSLeay::SESSION_set_timeout($s, $t);
	    # $s - value corresponding to openssl's SSL_SESSION structure
	    # $t - timeout (in seconds)
	    #
	    # returns: 1 on success

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_SESSION_get_time.html>

       o   set_timeout

	   Technically the same functionality as "SESSION_set_timeout".

	    my $rv = Net::SSLeay::set_timeout($ses, $t);

       Low level API: SSL_CTX_* related functions

       NOTE: Please note that the function described in this chapter have "SSL_" part stripped
       from their original openssl names.

       o   CTX_add_client_CA

	   Adds the CA name extracted from $cacert to the list of CAs sent to the client when
	   requesting a client certificate for $ctx.

	    my $rv = Net::SSLeay::CTX_add_client_CA($ctx, $cacert);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $cacert - value corresponding to openssl's X509 structure
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_client_CA_list.html>

       o   CTX_add_extra_chain_cert

	   Adds the certificate $x509 to the certificate chain presented together with the
	   certificate. Several certificates can be added one after the other.

	    my $rv = Net::SSLeay::CTX_add_extra_chain_cert($ctx, $x509);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $x509 - value corresponding to openssl's X509 structure
	    #
	    # returns: 1 on success, check out the error stack to find out the reason for failure otherwise

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_add_extra_chain_cert.html>

       o   CTX_add_session

	   Adds the session $ses to the context $ctx.

	    my $rv = Net::SSLeay::CTX_add_session($ctx, $ses);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $ses - value corresponding to openssl's SSL_SESSION structure
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_add_session.html>

       o   CTX_callback_ctrl

	   ??? (more info needed)

	    my $rv = Net::SSLeay::CTX_callback_ctrl($ctx, $cmd, $fp);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $cmd - (integer) command id
	    # $fp - (function pointer) ???
	    #
	    # returns: ???

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_ctrl.html>

       o   CTX_check_private_key

	   Checks the consistency of a private key with the corresponding certificate loaded into
	   $ctx.

	    my $rv = Net::SSLeay::CTX_check_private_key($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: 1 on success, otherwise check out the error stack to find out the reason

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_use_certificate.html>

       o   CTX_ctrl

	   Internal handling function for SSL_CTX objects.

	   BEWARE: openssl doc says: This function should never be called directly!

	    my $rv = Net::SSLeay::CTX_ctrl($ctx, $cmd, $larg, $parg);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $cmd - (integer) command id
	    # $larg - (integer) long ???
	    # $parg - (string/pointer) ???
	    #
	    # returns: (long) result of given command ???

	    #valid $cmd values
	     1 - SSL_CTRL_NEED_TMP_RSA
	     2 - SSL_CTRL_SET_TMP_RSA
	     3 - SSL_CTRL_SET_TMP_DH
	     4 - SSL_CTRL_SET_TMP_ECDH
	     5 - SSL_CTRL_SET_TMP_RSA_CB
	     6 - SSL_CTRL_SET_TMP_DH_CB
	     7 - SSL_CTRL_SET_TMP_ECDH_CB
	     8 - SSL_CTRL_GET_SESSION_REUSED
	     9 - SSL_CTRL_GET_CLIENT_CERT_REQUEST
	    10 - SSL_CTRL_GET_NUM_RENEGOTIATIONS
	    11 - SSL_CTRL_CLEAR_NUM_RENEGOTIATIONS
	    12 - SSL_CTRL_GET_TOTAL_RENEGOTIATIONS
	    13 - SSL_CTRL_GET_FLAGS
	    14 - SSL_CTRL_EXTRA_CHAIN_CERT
	    15 - SSL_CTRL_SET_MSG_CALLBACK
	    16 - SSL_CTRL_SET_MSG_CALLBACK_ARG
	    17 - SSL_CTRL_SET_MTU
	    20 - SSL_CTRL_SESS_NUMBER
	    21 - SSL_CTRL_SESS_CONNECT
	    22 - SSL_CTRL_SESS_CONNECT_GOOD
	    23 - SSL_CTRL_SESS_CONNECT_RENEGOTIATE
	    24 - SSL_CTRL_SESS_ACCEPT
	    25 - SSL_CTRL_SESS_ACCEPT_GOOD
	    26 - SSL_CTRL_SESS_ACCEPT_RENEGOTIATE
	    27 - SSL_CTRL_SESS_HIT
	    28 - SSL_CTRL_SESS_CB_HIT
	    29 - SSL_CTRL_SESS_MISSES
	    30 - SSL_CTRL_SESS_TIMEOUTS
	    31 - SSL_CTRL_SESS_CACHE_FULL
	    32 - SSL_CTRL_OPTIONS
	    33 - SSL_CTRL_MODE
	    40 - SSL_CTRL_GET_READ_AHEAD
	    41 - SSL_CTRL_SET_READ_AHEAD
	    42 - SSL_CTRL_SET_SESS_CACHE_SIZE
	    43 - SSL_CTRL_GET_SESS_CACHE_SIZE
	    44 - SSL_CTRL_SET_SESS_CACHE_MODE
	    45 - SSL_CTRL_GET_SESS_CACHE_MODE
	    50 - SSL_CTRL_GET_MAX_CERT_LIST
	    51 - SSL_CTRL_SET_MAX_CERT_LIST
	    52 - SSL_CTRL_SET_MAX_SEND_FRAGMENT
	    53 - SSL_CTRL_SET_TLSEXT_SERVERNAME_CB
	    54 - SSL_CTRL_SET_TLSEXT_SERVERNAME_ARG
	    55 - SSL_CTRL_SET_TLSEXT_HOSTNAME
	    56 - SSL_CTRL_SET_TLSEXT_DEBUG_CB
	    57 - SSL_CTRL_SET_TLSEXT_DEBUG_ARG
	    58 - SSL_CTRL_GET_TLSEXT_TICKET_KEYS
	    59 - SSL_CTRL_SET_TLSEXT_TICKET_KEYS
	    60 - SSL_CTRL_SET_TLSEXT_OPAQUE_PRF_INPUT
	    61 - SSL_CTRL_SET_TLSEXT_OPAQUE_PRF_INPUT_CB
	    62 - SSL_CTRL_SET_TLSEXT_OPAQUE_PRF_INPUT_CB_ARG
	    63 - SSL_CTRL_SET_TLSEXT_STATUS_REQ_CB
	    64 - SSL_CTRL_SET_TLSEXT_STATUS_REQ_CB_ARG
	    65 - SSL_CTRL_SET_TLSEXT_STATUS_REQ_TYPE
	    66 - SSL_CTRL_GET_TLSEXT_STATUS_REQ_EXTS
	    67 - SSL_CTRL_SET_TLSEXT_STATUS_REQ_EXTS
	    68 - SSL_CTRL_GET_TLSEXT_STATUS_REQ_IDS
	    69 - SSL_CTRL_SET_TLSEXT_STATUS_REQ_IDS
	    70 - SSL_CTRL_GET_TLSEXT_STATUS_REQ_OCSP_RESP
	    71 - SSL_CTRL_SET_TLSEXT_STATUS_REQ_OCSP_RESP
	    72 - SSL_CTRL_SET_TLSEXT_TICKET_KEY_CB
	    73 - DTLS_CTRL_GET_TIMEOUT
	    74 - DTLS_CTRL_HANDLE_TIMEOUT
	    75 - DTLS_CTRL_LISTEN
	    76 - SSL_CTRL_GET_RI_SUPPORT
	    77 - SSL_CTRL_CLEAR_OPTIONS
	    78 - SSL_CTRL_CLEAR_MODE

	    82 - SSL_CTRL_GET_EXTRA_CHAIN_CERTS
	    83 - SSL_CTRL_CLEAR_EXTRA_CHAIN_CERTS

	    88 - SSL_CTRL_CHAIN
	    89 - SSL_CTRL_CHAIN_CERT

	    90 - SSL_CTRL_GET_CURVES
	    91 - SSL_CTRL_SET_CURVES
	    92 - SSL_CTRL_SET_CURVES_LIST
	    93 - SSL_CTRL_GET_SHARED_CURVE
	    94 - SSL_CTRL_SET_ECDH_AUTO
	    97 - SSL_CTRL_SET_SIGALGS
	    98 - SSL_CTRL_SET_SIGALGS_LIST
	    99 - SSL_CTRL_CERT_FLAGS
	    100 - SSL_CTRL_CLEAR_CERT_FLAGS
	    101 - SSL_CTRL_SET_CLIENT_SIGALGS
	    102 - SSL_CTRL_SET_CLIENT_SIGALGS_LIST
	    103 - SSL_CTRL_GET_CLIENT_CERT_TYPES
	    104 - SSL_CTRL_SET_CLIENT_CERT_TYPES
	    105 - SSL_CTRL_BUILD_CERT_CHAIN
	    106 - SSL_CTRL_SET_VERIFY_CERT_STORE
	    107 - SSL_CTRL_SET_CHAIN_CERT_STORE
	    108 - SSL_CTRL_GET_PEER_SIGNATURE_NID
	    109 - SSL_CTRL_GET_SERVER_TMP_KEY
	    110 - SSL_CTRL_GET_RAW_CIPHERLIST
	    111 - SSL_CTRL_GET_EC_POINT_FORMATS
	    112 - SSL_CTRL_GET_TLSA_RECORD
	    113 - SSL_CTRL_SET_TLSA_RECORD
	    114 - SSL_CTRL_PULL_TLSA_RECORD

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_ctrl.html>

       o   CTX_flush_sessions

	   Causes a run through the session cache of $ctx to remove sessions expired at time $tm.

	    Net::SSLeay::CTX_flush_sessions($ctx, $tm);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $tm - specifies the time which should be used for the expiration test (seconds since 1.1.1970)
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_flush_sessions.html>

       o   CTX_free

	   Free an allocated SSL_CTX object.

	    Net::SSLeay::CTX_free($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_free.html>

       o   CTX_get_app_data

	   Can be used to get application defined value/data.

	    my $rv = Net::SSLeay::CTX_get_app_data($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: string/buffer/pointer ???

       o   CTX_set_app_data

	   Can be used to set some application defined value/data.

	    my $rv = Net::SSLeay::CTX_set_app_data($ctx, $arg);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $arg - (string/buffer/pointer ???) data
	    #
	    # returns: ???

       o   CTX_get_cert_store

	   Returns the current certificate verification storage.

	    my $rv = Net::SSLeay::CTX_get_cert_store($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: value corresponding to openssl's X509_STORE structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_cert_store.html>

       o   CTX_get_client_CA_list

	   Returns the list of client CAs explicitly set for $ctx using "CTX_set_client_CA_list".

	    my $rv = Net::SSLeay::CTX_get_client_CA_list($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: value corresponding to openssl's X509_NAME_STACK structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_get_client_CA_list.html>

       o   CTX_get_ex_data

	   Is used to retrieve the information for index $idx from $ctx.

	    my $rv = Net::SSLeay::CTX_get_ex_data($ssl, $idx);
	    # $ssl - value corresponding to openssl's SSL_CTX structure
	    # $idx - (integer) index for application specific data
	    #
	    # returns: pointer to ???

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_get_ex_new_index.html>

       o   CTX_get_ex_new_index

	   Is used to register a new index for application specific data.

	    my $rv = Net::SSLeay::CTX_get_ex_new_index($argl, $argp, $new_func, $dup_func, $free_func);
	    # $argl - (long) ???
	    # $argp - (pointer) ???
	    # $new_func - function pointer ??? (CRYPTO_EX_new *)
	    # $dup_func - function pointer ??? (CRYPTO_EX_dup *)
	    # $free_func - function pointer ??? (CRYPTO_EX_free *)
	    #
	    # returns: (integer) ???

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_get_ex_new_index.html>

       o   CTX_get_mode

	   Returns the mode set for ctx.

	    my $rv = Net::SSLeay::CTX_get_mode($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: mode (bitmask)

	    #to decode the return value (bitmask) use:
	    0x00000001 corresponds to SSL_MODE_ENABLE_PARTIAL_WRITE
	    0x00000002 corresponds to SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER
	    0x00000004 corresponds to SSL_MODE_AUTO_RETRY
	    0x00000008 corresponds to SSL_MODE_NO_AUTO_CHAIN
	    0x00000010 corresponds to SSL_MODE_RELEASE_BUFFERS
	    (note: some of the bits might not be supported by older openssl versions)

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_mode.html>

       o   CTX_set_mode

	   Adds the mode set via bitmask in $mode to $ctx. Options already set before are not
	   cleared.

	    my $rv = Net::SSLeay::CTX_set_mode($ctx, $mode);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $mode - mode bitmask
	    #
	    # returns: the new mode bitmask after adding $mode

	   For bitmask details see "CTX_get_mode" (above).

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_mode.html>

       o   CTX_get_options

	   Returns the options (bitmask) set for $ctx.

	    my $rv = Net::SSLeay::CTX_get_options($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: options (bitmask)

	    #to decode the return value (bitmask) use:
	    0x00000001 corresponds to SSL_OP_MICROSOFT_SESS_ID_BUG
	    0x00000002 corresponds to SSL_OP_NETSCAPE_CHALLENGE_BUG
	    0x00000004 corresponds to SSL_OP_LEGACY_SERVER_CONNECT
	    0x00000008 corresponds to SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG
	    0x00000010 corresponds to SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG
	    0x00000020 corresponds to SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER
	    0x00000040 corresponds to SSL_OP_MSIE_SSLV2_RSA_PADDING
	    0x00000080 corresponds to SSL_OP_SSLEAY_080_CLIENT_DH_BUG
	    0x00000100 corresponds to SSL_OP_TLS_D5_BUG
	    0x00000200 corresponds to SSL_OP_TLS_BLOCK_PADDING_BUG
	    0x00000800 corresponds to SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS
	    0x80000FFF corresponds to SSL_OP_ALL
	    0x00001000 corresponds to SSL_OP_NO_QUERY_MTU
	    0x00002000 corresponds to SSL_OP_COOKIE_EXCHANGE
	    0x00004000 corresponds to SSL_OP_NO_TICKET
	    0x00008000 corresponds to SSL_OP_CISCO_ANYCONNECT
	    0x00010000 corresponds to SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION
	    0x00020000 corresponds to SSL_OP_NO_COMPRESSION
	    0x00040000 corresponds to SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION
	    0x00080000 corresponds to SSL_OP_SINGLE_ECDH_USE
	    0x00100000 corresponds to SSL_OP_SINGLE_DH_USE
	    0x00200000 corresponds to SSL_OP_EPHEMERAL_RSA
	    0x00400000 corresponds to SSL_OP_CIPHER_SERVER_PREFERENCE
	    0x00800000 corresponds to SSL_OP_TLS_ROLLBACK_BUG
	    0x01000000 corresponds to SSL_OP_NO_SSLv2
	    0x02000000 corresponds to SSL_OP_NO_SSLv3
	    0x04000000 corresponds to SSL_OP_NO_TLSv1
	    0x08000000 corresponds to SSL_OP_PKCS1_CHECK_1
	    0x10000000 corresponds to SSL_OP_PKCS1_CHECK_2
	    0x20000000 corresponds to SSL_OP_NETSCAPE_CA_DN_BUG
	    0x40000000 corresponds to SSL_OP_NETSCAPE_DEMO_CIPHER_CHANGE_BUG
	    0x80000000 corresponds to SSL_OP_CRYPTOPRO_TLSEXT_BUG
	    (note: some of the bits might not be supported by older openssl versions)

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_options.html>

       o   CTX_set_options

	   Adds the options set via bitmask in $options to ctx. Options already set before are
	   not cleared.

	    Net::SSLeay::CTX_set_options($ctx, $options);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $options - options bitmask
	    #
	    # returns: the new options bitmask after adding $options

	   For bitmask details see "CTX_get_options" (above).

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_options.html>

       o   CTX_get_quiet_shutdown

	   Returns the 'quiet shutdown' setting of $ctx.

	    my $rv = Net::SSLeay::CTX_get_quiet_shutdown($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: (integer) the current setting

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_quiet_shutdown.html>

       o   CTX_get_read_ahead

	    my $rv = Net::SSLeay::CTX_get_read_ahead($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: (integer) read_ahead value

       o   CTX_get_session_cache_mode

	   Returns the currently used cache mode (bitmask).

	    my $rv = Net::SSLeay::CTX_get_session_cache_mode($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: mode (bitmask)

	    #to decode the return value (bitmask) use:
	    0x0000 corresponds to SSL_SESS_CACHE_OFF
	    0x0001 corresponds to SSL_SESS_CACHE_CLIENT
	    0x0002 corresponds to SSL_SESS_CACHE_SERVER
	    0x0080 corresponds to SSL_SESS_CACHE_NO_AUTO_CLEAR
	    0x0100 corresponds to SSL_SESS_CACHE_NO_INTERNAL_LOOKUP
	    0x0200 corresponds to SSL_SESS_CACHE_NO_INTERNAL_STORE
	    (note: some of the bits might not be supported by older openssl versions)

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_session_cache_mode.html>

       o   CTX_set_session_cache_mode

	   Enables/disables session caching by setting the operational mode for $ctx to $mode.

	    my $rv = Net::SSLeay::CTX_set_session_cache_mode($ctx, $mode);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $mode - mode (bitmask)
	    #
	    # returns: previously set cache mode

	   For bitmask details see "CTX_get_session_cache_mode" (above).

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_session_cache_mode.html>

       o   CTX_get_timeout

	   Returns the currently set timeout value for $ctx.

	    my $rv = Net::SSLeay::CTX_get_timeout($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: timeout in seconds

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_timeout.html>

       o   CTX_get_verify_depth

	   Returns the verification depth limit currently set in $ctx. If no limit has been
	   explicitly set, -1 is returned and the default value will be used.",

	    my $rv = Net::SSLeay::CTX_get_verify_depth($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: depth limit currently set in $ctx, -1 if no limit has been explicitly set

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_get_verify_mode.html>

       o   CTX_get_verify_mode

	   Returns the verification mode (bitmask) currently set in $ctx.

	    my $rv = Net::SSLeay::CTX_get_verify_mode($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: mode (bitmask)

	    #to decode the return value (bitmask) use:
	    0x00 corresponds to SSL_VERIFY_NONE
	    0x01 corresponds to SSL_VERIFY_PEER
	    0x02 corresponds to SSL_VERIFY_FAIL_IF_NO_PEER_CERT
	    0x04 corresponds to SSL_VERIFY_CLIENT_ONCE
	    (note: some of the bits might not be supported by older openssl versions)

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_get_verify_mode.html>

       o   CTX_set_verify

	   Sets the verification flags for $ctx to be $mode and specifies the verify_callback
	   function to be used.

	    Net::SSLeay::CTX_set_verify($ctx, $mode, $callback);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $mode - mode (bitmask)
	    # $callback - [optional] reference to perl callback function
	    #
	    # returns: no return value

	   For bitmask details see "CTX_get_verify_mode" (above).

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_verify.html>

       o   CTX_load_verify_locations

	   Specifies the locations for $ctx, at which CA certificates for verification purposes
	   are located. The certificates available via $CAfile and $CApath are trusted.

	    my $rv = Net::SSLeay::CTX_load_verify_locations($ctx, $CAfile, $CApath);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $CAfile - (string) file of CA certificates in PEM format, the file can contain several CA certificates (or '')
	    # $CApath - (string) directory containing CA certificates in PEM format (or '')
	    #
	    # returns: 1 on success, 0 on failure (check the error stack to find out the reason)

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_load_verify_locations.html>

       o   CTX_need_tmp_RSA

	   Return the result of "SSL_CTX_ctrl(ctx,SSL_CTRL_NEED_TMP_RSA,0,NULL)"

	    my $rv = Net::SSLeay::CTX_need_tmp_RSA($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: result of SSL_CTRL_NEED_TMP_RSA command

       o   CTX_new

	   The same as "CTX_v23_new"

	    my $rv = Net::SSLeay::CTX_new();
	    #
	    # returns: value corresponding to openssl's SSL_CTX structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_new.html>

       o   CTX_v2_new

	   Creates a new SSL_CTX object - based on SSLv2_method() - as framework to establish
	   TLS/SSL enabled connections.

	    my $rv = Net::SSLeay::CTX_v2_new();
	    #
	    # returns: value corresponding to openssl's SSL_CTX structure (0 on failure)

       o   CTX_v23_new

	   Creates a new SSL_CTX object - based on SSLv23_method() - as framework to establish
	   TLS/SSL enabled connections.

	    my $rv = Net::SSLeay::CTX_v23_new();
	    #
	    # returns: value corresponding to openssl's SSL_CTX structure (0 on failure)

       o   CTX_v3_new

	   Creates a new SSL_CTX object - based on SSLv3_method() - as framework to establish
	   TLS/SSL enabled connections.

	    my $rv = Net::SSLeay::CTX_v3_new();
	    #
	    # returns: value corresponding to openssl's SSL_CTX structure (0 on failure)

       o   CTX_tlsv1_new

	   Creates a new SSL_CTX object - based on TLSv1_method() - as framework to establish
	   TLS/SSL enabled connections.

	    my $rv = Net::SSLeay::CTX_tlsv1_new();
	    #
	    # returns: value corresponding to openssl's SSL_CTX structure (0 on failure)

       o   CTX_tlsv1_1_new

	   Creates a new SSL_CTX object - based on TLSv1_1_method() - as framework to establish
	   TLS/SSL enabled connections. Only available where supported by the underlying openssl.

	    my $rv = Net::SSLeay::CTX_tlsv1_1_new();
	    #
	    # returns: value corresponding to openssl's SSL_CTX structure (0 on failure)

       o   CTX_tlsv1_2_new

	   Creates a new SSL_CTX object - based on TLSv1_2_method() - as framework to establish
	   TLS/SSL enabled connections. Only available where supported by the underlying openssl.

	    my $rv = Net::SSLeay::CTX_tlsv1_2_new();
	    #
	    # returns: value corresponding to openssl's SSL_CTX structure (0 on failure)

       o   CTX_new_with_method

	   Creates a new SSL_CTX object based on $meth method

	    my $rv = Net::SSLeay::CTX_new_with_method($meth);
	    # $meth - value corresponding to openssl's SSL_METHOD structure
	    #
	    # returns: value corresponding to openssl's SSL_CTX structure (0 on failure)

	    #example
	    my $ctx = Net::SSLeay::CTX_new_with_method(&Net::SSLeay::TLSv1_method);

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_new.html>

       o   CTX_remove_session

	   Removes the session $ses from the context $ctx.

	    my $rv = Net::SSLeay::CTX_remove_session($ctx, $ses);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $ses - value corresponding to openssl's SSL_SESSION structure
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_add_session.html>

       o   CTX_sess_accept

	    my $rv = Net::SSLeay::CTX_sess_accept($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: number of started SSL/TLS handshakes in server mode

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_sess_number.html>

       o   CTX_sess_accept_good

	    my $rv = Net::SSLeay::CTX_sess_accept_good($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: number of successfully established SSL/TLS sessions in server mode

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_sess_number.html>

       o   CTX_sess_accept_renegotiate

	    my $rv = Net::SSLeay::CTX_sess_accept_renegotiate($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: number of start renegotiations in server mode

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_sess_number.html>

       o   CTX_sess_cache_full

	    my $rv = Net::SSLeay::CTX_sess_cache_full($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: number of sessions that were removed because the maximum session cache size was exceeded

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_sess_number.html>

       o   CTX_sess_cb_hits

	    my $rv = Net::SSLeay::CTX_sess_cb_hits($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: number of successfully retrieved sessions from the external session cache in server mode

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_sess_number.html>

       o   CTX_sess_connect

	    my $rv = Net::SSLeay::CTX_sess_connect($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: number of started SSL/TLS handshakes in client mode

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_sess_number.html>

       o   CTX_sess_connect_good

	    my $rv = Net::SSLeay::CTX_sess_connect_good($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: number of successfully established SSL/TLS sessions in client mode

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_sess_number.html>

       o   CTX_sess_connect_renegotiate

	    my $rv = Net::SSLeay::CTX_sess_connect_renegotiate($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: number of start renegotiations in client mode

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_sess_number.html>

       o   CTX_sess_get_cache_size

	   Returns the currently valid session cache size.

	    my $rv = Net::SSLeay::CTX_sess_get_cache_size($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: current size

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_sess_set_cache_size.html>

       o   CTX_sess_hits

	    my $rv = Net::SSLeay::CTX_sess_hits($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: number of successfully reused sessions

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_sess_number.html>

       o   CTX_sess_misses

	    my $rv = Net::SSLeay::CTX_sess_misses($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: number of sessions proposed by clients that were not found in the internal session cache in server mode

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_sess_number.html>

       o   CTX_sess_number

	    my $rv = Net::SSLeay::CTX_sess_number($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: current number of sessions in the internal session cache

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_sess_number.html>

       o   CTX_sess_set_cache_size

	   Sets the size of the internal session cache of context $ctx to $size.

	    Net::SSLeay::CTX_sess_set_cache_size($ctx, $size);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $size - cache size (0 = unlimited)
	    #
	    # returns: previously valid size

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_sess_set_cache_size.html>

       o   CTX_sess_timeouts

	   Returns the number of sessions proposed by clients and either found in the internal or
	   external session cache in server mode, but that were invalid due to timeout. These
	   sessions are not included in the SSL_CTX_sess_hits count.

	    my $rv = Net::SSLeay::CTX_sess_timeouts($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: number of sessions

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_sess_number.html>

       o   CTX_sessions

	   Returns a pointer to the lhash databases containing the internal session cache for
	   ctx.

	    my $rv = Net::SSLeay::CTX_sessions($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: value corresponding to openssl's LHASH structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_sessions.html>

       o   CTX_set1_param

	   Applies X509 verification parameters $vpm on $ctx

	    my $rv = Net::SSLeay::CTX_set1_param($ctx, $vpm);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $vpm - value corresponding to openssl's X509_VERIFY_PARAM structure
	    #
	    # returns: 1 on success, 0 on failure

       o   CTX_set_cert_store

	   Sets/replaces the certificate verification storage of $ctx to/with $store.

	    Net::SSLeay::CTX_set_cert_store($ctx, $store);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $store - value corresponding to openssl's X509_STORE structure
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_cert_store.html>

       o   CTX_set_cert_verify_callback

	   Sets the verification callback function for $ctx. SSL objects that are created from
	   $ctx inherit the setting valid at the time when "Net::SSLeay::new($ctx)" is called.

	    Net::SSLeay::CTX_set_cert_verify_callback($ctx, $func, $data);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $func - perl reference to callback function
	    # $data - [optional] data that will be passed to callback function when invoked
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_cert_verify_callback.html>

       o   CTX_set_cipher_list

	   Sets the list of available ciphers for $ctx using the control string $str.  The list
	   of ciphers is inherited by all ssl objects created from $ctx.

	    my $rv = Net::SSLeay::CTX_set_cipher_list($s, $str);
	    # $s - value corresponding to openssl's SSL_CTX structure
	    # $str - (string) cipher list e.g. '3DES:+RSA'
	    #
	    # returns: 1 if any cipher could be selected and 0 on complete failure

	   The format of $str is described in <http://www.openssl.org/docs/apps/ciphers.html>

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_cipher_list.html>

       o   CTX_set_client_CA_list

	   Sets the list of CAs sent to the client when requesting a client certificate for $ctx.

	    Net::SSLeay::CTX_set_client_CA_list($ctx, $list);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $list - value corresponding to openssl's X509_NAME_STACK structure
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_client_CA_list.html>

       o   CTX_set_default_passwd_cb

	   Sets the default password callback called when loading/storing a PEM certificate with
	   encryption.

	    Net::SSLeay::CTX_set_default_passwd_cb($ctx, $func);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $func - perl reference to callback function
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_default_passwd_cb.html>

       o   CTX_set_default_passwd_cb_userdata

	   Sets a pointer to userdata which will be provided to the password callback on
	   invocation.

	    Net::SSLeay::CTX_set_default_passwd_cb_userdata($ctx, $userdata);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $userdata - data that will be passed to callback function when invoked
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_default_passwd_cb.html>

       o   CTX_set_default_verify_paths

	   ??? (more info needed)

	    my $rv = Net::SSLeay::CTX_set_default_verify_paths($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: 1 on success, 0 on failure

       o   CTX_set_ex_data

	   Is used to store application data at $data for $idx into the $ctx object.

	    my $rv = Net::SSLeay::CTX_set_ex_data($ssl, $idx, $data);
	    # $ssl - value corresponding to openssl's SSL_CTX structure
	    # $idx - (integer) ???
	    # $data - (pointer) ???
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_get_ex_new_index.html>

       o   CTX_set_purpose

	    my $rv = Net::SSLeay::CTX_set_purpose($s, $purpose);
	    # $s - value corresponding to openssl's SSL_CTX structure
	    # $purpose - (integer) purpose identifier
	    #
	    # returns: 1 on success, 0 on failure

	    #avainable purpose identifier
	    1 - X509_PURPOSE_SSL_CLIENT
	    2 - X509_PURPOSE_SSL_SERVER
	    3 - X509_PURPOSE_NS_SSL_SERVER
	    4 - X509_PURPOSE_SMIME_SIGN
	    5 - X509_PURPOSE_SMIME_ENCRYPT
	    6 - X509_PURPOSE_CRL_SIGN
	    7 - X509_PURPOSE_ANY
	    8 - X509_PURPOSE_OCSP_HELPER
	    9 - X509_PURPOSE_TIMESTAMP_SIGN

	    #or use corresponding constants
	    $purpose = &Net::SSLeay::X509_PURPOSE_SSL_CLIENT;
	    ...
	    $purpose = &Net::SSLeay::X509_PURPOSE_TIMESTAMP_SIGN;

       o   CTX_set_quiet_shutdown

	   Sets the 'quiet shutdown' flag for $ctx to be mode. SSL objects created from $ctx
	   inherit the mode valid at the time "Net::SSLeay::new($ctx)" is called.

	    Net::SSLeay::CTX_set_quiet_shutdown($ctx, $mode);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $mode - 0 or 1
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_quiet_shutdown.html>

       o   CTX_set_read_ahead

	    my $rv = Net::SSLeay::CTX_set_read_ahead($ctx, $val);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $val - read_ahead value to be set
	    #
	    # returns: the original read_ahead value

       o   CTX_set_session_id_context

	   Sets the context $sid_ctx of length $sid_ctx_len within which a session can be reused
	   for the $ctx object.

	    my $rv = Net::SSLeay::CTX_set_session_id_context($ctx, $sid_ctx, $sid_ctx_len);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $sid_ctx - data buffer
	    # $sid_ctx_len - length of data in $sid_ctx
	    #
	    # returns: 1 on success, 0 on failure (the error is logged to the error stack)

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_session_id_context.html>

       o   CTX_set_ssl_version

	   Sets a new default TLS/SSL method for SSL objects newly created from this $ctx.  SSL
	   objects already created with "Net::SSLeay::new($ctx)" are not affected, except when
	   "Net::SSLeay:clear($ssl)" is being called.

	    my $rv = Net::SSLeay::CTX_set_ssl_version($ctx, $meth);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $meth - value corresponding to openssl's SSL_METHOD structure
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_ssl_version.html>

       o   CTX_set_timeout

	   Sets the timeout for newly created sessions for $ctx to $t. The timeout value $t must
	   be given in seconds.

	    my $rv = Net::SSLeay::CTX_set_timeout($ctx, $t);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $t - timeout in seconds
	    #
	    # returns: previously set timeout value

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_timeout.html>

       o   CTX_set_tmp_dh

	   Sets DH parameters to be used to be $dh. The key is inherited by all ssl objects
	   created from $ctx.

	    my $rv = Net::SSLeay::CTX_set_tmp_dh($ctx, $dh);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $dh - value corresponding to openssl's DH structure
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_tmp_dh_callback.html>

       o   CTX_set_tmp_dh_callback

	   Sets the callback function for $ctx to be used when a DH parameters are required to
	   $tmp_dh_callback.

	    Net::SSLeay::CTX_set_tmp_dh_callback($ctx, $tmp_dh_callback);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # tmp_dh_callback - (function pointer) ???
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_tmp_dh_callback.html>

       o   CTX_set_tmp_rsa

	   Sets the temporary/ephemeral RSA key to be used to be $rsa.

	    my $rv = Net::SSLeay::CTX_set_tmp_rsa($ctx, $rsa);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $rsa - value corresponding to openssl's RSA structure
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_tmp_rsa_callback.html>

       o   CTX_set_tmp_rsa_callback

	   Sets the callback function for ctx to be used when a temporary/ephemeral RSA key is
	   required to $tmp_rsa_callback.

	   ??? (does this function really work?)

	    Net::SSLeay::CTX_set_tmp_rsa_callback($ctx, $tmp_rsa_callback);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $tmp_rsa_callback - (function pointer) ???
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_tmp_rsa_callback.html>

       o   CTX_set_trust

	    my $rv = Net::SSLeay::CTX_set_trust($s, $trust);
	    # $s - value corresponding to openssl's SSL_CTX structure
	    # $trust - (integer) trust identifier
	    #
	    # returns: the original value

	    #available trust identifiers
	    1 - X509_TRUST_COMPAT
	    2 - X509_TRUST_SSL_CLIENT
	    3 - X509_TRUST_SSL_SERVER
	    4 - X509_TRUST_EMAIL
	    5 - X509_TRUST_OBJECT_SIGN
	    6 - X509_TRUST_OCSP_SIGN
	    7 - X509_TRUST_OCSP_REQUEST
	    8 - X509_TRUST_TSA

	    #or use corresponding constants
	    $trust = &Net::SSLeay::X509_TRUST_COMPAT;
	    ...
	    $trust = &Net::SSLeay::X509_TRUST_TSA;

       o   CTX_set_verify_depth

	   Sets the maximum depth for the certificate chain verification that shall be allowed
	   for ctx.

	    Net::SSLeay::CTX_set_verify_depth($ctx, $depth);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $depth - max. depth
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_verify.html>

       o   CTX_use_PKCS12_file

	   Adds the certificate and private key from PKCS12 file $p12filename to $ctx.

	    my $rv = Net::SSLeay::CTX_use_PKCS12_file($ctx, $p12filename, $password);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $p12filename - (string) filename
	    # $password - (string) password to decrypt private key
	    #
	    # returns: 1 on success, 0 on failure

       o   CTX_use_PrivateKey

	   Adds the private key $pkey to $ctx.

	    my $rv = Net::SSLeay::CTX_use_PrivateKey($ctx, $pkey);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $pkey - value corresponding to openssl's EVP_PKEY structure
	    #
	    # returns: 1 on success, otherwise check out the error stack to find out the reason

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_use_certificate.html>

       o   CTX_use_PrivateKey_file

	   Adds the first private key found in $file to $ctx.

	    my $rv = Net::SSLeay::CTX_use_PrivateKey_file($ctx, $file, $type);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $file - (string) file name
	    # $type - (integer) type - use constants &Net::SSLeay::FILETYPE_PEM or &Net::SSLeay::FILETYPE_ASN1
	    #
	    # returns: 1 on success, otherwise check out the error stack to find out the reason

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_use_certificate.html>

       o   CTX_use_RSAPrivateKey

	   Adds the RSA private key $rsa to $ctx.

	    my $rv = Net::SSLeay::CTX_use_RSAPrivateKey($ctx, $rsa);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $rsa - value corresponding to openssl's RSA structure
	    #
	    # returns: 1 on success, otherwise check out the error stack to find out the reason

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_use_certificate.html>

       o   CTX_use_RSAPrivateKey_file

	   Adds the first RSA private key found in $file to $ctx.

	    my $rv = Net::SSLeay::CTX_use_RSAPrivateKey_file($ctx, $file, $type);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $file - (string) file name
	    # $type - (integer) type - use constants &Net::SSLeay::FILETYPE_PEM or &Net::SSLeay::FILETYPE_ASN1
	    #
	    # returns: 1 on success, otherwise check out the error stack to find out the reason

       o   CTX_use_certificate

	   Loads the certificate $x into $ctx

	    my $rv = Net::SSLeay::CTX_use_certificate($ctx, $x);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $x - value corresponding to openssl's X509 structure
	    #
	    # returns: 1 on success, otherwise check out the error stack to find out the reason

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_use_certificate.html>

       o   CTX_use_certificate_chain_file

	   Loads a certificate chain from $file into $ctx. The certificates must be in PEM format
	   and must be sorted starting with the subject's certificate (actual client or server
	   certificate), followed by intermediate CA certificates if applicable, and ending at
	   the highest level (root) CA.

	    my $rv = Net::SSLeay::CTX_use_certificate_chain_file($ctx, $file);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $file - (string) file name
	    #
	    # returns: 1 on success, otherwise check out the error stack to find out the reason

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_use_certificate.html>

       o   CTX_use_certificate_file

	   Loads the first certificate stored in $file into $ctx.

	    my $rv = Net::SSLeay::CTX_use_certificate_file($ctx, $file, $type);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $file - (string) file name
	    # $type - (integer) type - use constants &Net::SSLeay::FILETYPE_PEM or &Net::SSLeay::FILETYPE_ASN1
	    #
	    # returns: 1 on success, otherwise check out the error stack to find out the reason

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_use_certificate.html>

       Low level API: SSL_* related functions

       NOTE: Please note that the function described in this chapter have "SSL_" part stripped
       from their original openssl names.

       o   new

	   Creates a new SSL structure which is needed to hold the data for a TLS/SSL connection.
	   The new structure inherits the settings of the underlying context $ctx: connection
	   method (SSLv2/v3/TLSv1), options, verification settings, timeout settings.

	    my $rv = Net::SSLeay::new($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: value corresponding to openssl's SSL structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_new.html>

       o   accept

	   Waits for a TLS/SSL client to initiate the TLS/SSL handshake. The communication
	   channel must already have been set and assigned to the ssl by setting an underlying
	   BIO.

	    my $rv = Net::SSLeay::accept($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: 1 = success, 0 = handshake not successfull, <0 = fatal error during handshake

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_accept.html>

       o   add_client_CA

	   Adds the CA name extracted from cacert to the list of CAs sent to the client when
	   requesting a client certificate for the chosen ssl, overriding the setting valid for
	   ssl's SSL_CTX object.

	    my $rv = Net::SSLeay::add_client_CA($ssl, $x);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $x - value corresponding to openssl's X509 structure
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_client_CA_list.html>

       o   callback_ctrl

	   ??? (more info needed)

	    my $rv = Net::SSLeay::callback_ctrl($ssl, $cmd, $fp);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $cmd - (integer) command id
	    # $fp - (function pointer) ???
	    #
	    # returns: ???

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_ctrl.html>

       o   check_private_key

	   Checks the consistency of a private key with the corresponding certificate loaded into
	   $ssl

	    my $rv = Net::SSLeay::check_private_key($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: 1 on success, otherwise check out the error stack to find out the reason

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_use_certificate.html>

       o   clear

	   Reset SSL object to allow another connection.

	    Net::SSLeay::clear($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_clear.html>

       o   connect

	   Initiate the TLS/SSL handshake with an TLS/SSL server.

	    my $rv = Net::SSLeay::connect($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: 1 = success, 0 = handshake not successfull, <0 = fatal error during handshake

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_connect.html>

       o   copy_session_id

	   Copies the session structure fro $from to $to (+ also the private key and certificate
	   associated with $from).

	    Net::SSLeay::copy_session_id($to, $from);
	    # $to - value corresponding to openssl's SSL structure
	    # $from - value corresponding to openssl's SSL structure
	    #
	    # returns: no return value

       o   ctrl

	   Internal handling function for SSL objects.

	   BEWARE: openssl doc says: This function should never be called directly!

	    my $rv = Net::SSLeay::ctrl($ssl, $cmd, $larg, $parg);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $cmd - (integer) command id
	    # $larg - (integer) long ???
	    # $parg - (string/pointer) ???
	    #
	    # returns: (long) result of given command ???

	   For more details about valid $cmd values check "CTX_ctrl".

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_ctrl.html>

       o   do_handshake

	   Will wait for a SSL/TLS handshake to take place. If the connection is in client mode,
	   the handshake will be started. The handshake routines may have to be explicitly set in
	   advance using either SSL_set_connect_state or SSL_set_accept_state(3).

	    my $rv = Net::SSLeay::do_handshake($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: 1 = success, 0 = handshake not successfull, <0 = fatal error during handshake

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_do_handshake.html>

       o   dup

	   Returns a duplicate of $ssl.

	    my $rv = Net::SSLeay::dup($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: value corresponding to openssl's SSL structure (0 on failure)

       o   free

	   Free an allocated SSL structure.

	    Net::SSLeay::free($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_free.html>

       o   get_SSL_CTX

	   Returns a pointer to the SSL_CTX object, from which $ssl was created with
	   Net::SSLeay::new.

	    my $rv = Net::SSLeay::get_SSL_CTX($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: value corresponding to openssl's SSL_CTX structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_get_SSL_CTX.html>

       o   set_SSL_CTX

	   Sets the SSL_CTX the corresponds to an SSL session.

	    my $the_ssl_ctx = Net::SSLeay::set_SSL_CTX($ssl, $ssl_ctx);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $ssl_ctx - Change the ssl object to the given ssl_ctx
	    #
	    # returns - the ssl_ctx

       o   get_app_data

	   Can be used to get application defined value/data.

	    my $rv = Net::SSLeay::get_app_data($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: string/buffer/pointer ???

       o   set_app_data

	   Can be used to set some application defined value/data.

	    my $rv = Net::SSLeay::set_app_data($ssl, $arg);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $arg - (string/buffer/pointer ???) data
	    #
	    # returns: ???

       o   get_certificate

	   Gets X509 certificate from an established SSL connection.

	    my $rv = Net::SSLeay::get_certificate($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: value corresponding to openssl's X509 structure (0 on failure)

       o   get_cipher

	   Obtains the name of the currently used cipher.

	    my $rv = Net::SSLeay::get_cipher($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: (string) cipher name e.g. 'DHE-RSA-AES256-SHA' or '', when no session has been established.

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_get_current_cipher.html>

       o   get_cipher_bits

	   Obtain the number of secret/algorithm bits used.

	    my $rv = Net::SSLeay::get_cipher_bits($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: number of secret bits used by current cipher

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_get_current_cipher.html> and
	   <http://www.openssl.org/docs/ssl/SSL_CIPHER_get_name.html>

       o   get_cipher_list

	   Returns the name (string) of the SSL_CIPHER listed for $ssl with priority $n.

	    my $rv = Net::SSLeay::get_cipher_list($ssl, $n);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $n - (integer) priority
	    #
	    # returns: (string) cipher name e.g. 'EDH-DSS-DES-CBC3-SHA' or '' in case of error

	   Call Net::SSLeay::get_cipher_list with priority starting from 0 to obtain the sorted
	   list of available ciphers, until '' is returned:

	    my $priority = 0;
	    while (my $c = Net::SSLeay::get_cipher_list($ssl, $priority)) {
	      print "cipher[$priority] = $c\n";
	      $priority++;
	    }

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_get_ciphers.html>

       o   get_client_CA_list

	   Returns the list of client CAs explicitly set for $ssl using
	   "Net::SSleay::set_client_CA_list" or $ssl's SSL_CTX object with
	   "Net::SSLeay::CTX_set_client_CA_list", when in server mode.

	   In client mode, returns the list of client CAs sent from the server, if any.

	    my $rv = Net::SSLeay::get_client_CA_list($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: value corresponding to openssl's STACK_OF(X509_NAME) structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_get_client_CA_list.html>

       o   get_current_cipher

	   Returns the cipher actually used.

	    my $rv = Net::SSLeay::get_current_cipher($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: value corresponding to openssl's SSL_CIPHER structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_get_current_cipher.html>

       o   get_default_timeout

	   Returns the default timeout value assigned to SSL_SESSION objects negotiated for the
	   protocol valid for $ssl.

	    my $rv = Net::SSLeay::get_default_timeout($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: (long) timeout in seconds

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_get_default_timeout.html>

       o   get_error

	   Returns a result code for a preceding call to "connect", "accept", "do_handshake",
	   "read", "peek" or "write" on $ssl.

	    my $rv = Net::SSLeay::get_error($ssl, $ret);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $ret - return value of preceding TLS/SSL I/O operation
	    #
	    # returns: result code, which is one of the following values:
	    #  0 - SSL_ERROR_NONE
	    #  1 - SSL_ERROR_SSL
	    #  2 - SSL_ERROR_WANT_READ
	    #  3 - SSL_ERROR_WANT_WRITE
	    #  4 - SSL_ERROR_WANT_X509_LOOKUP
	    #  5 - SSL_ERROR_SYSCALL
	    #  6 - SSL_ERROR_ZERO_RETURN
	    #  7 - SSL_ERROR_WANT_CONNECT
	    #  8 - SSL_ERROR_WANT_ACCEPT

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_get_error.html>

       o   get_ex_data

	   Is used to retrieve the information for $idx from $ssl.

	    my $rv = Net::SSLeay::get_ex_data($ssl, $idx);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $idx - (integer) index for application specific data
	    #
	    # returns: pointer to ???

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_get_ex_new_index.html>

       o   set_ex_data

	   Is used to store application data at $data for $idx into the $ssl object.

	    my $rv = Net::SSLeay::set_ex_data($ssl, $idx, $data);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $idx - (integer) ???
	    # $data - (pointer) ???
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_get_ex_new_index.html>

       o   get_ex_new_index

	   Is used to register a new index for application specific data.

	    my $rv = Net::SSLeay::get_ex_new_index($argl, $argp, $new_func, $dup_func, $free_func);
	    # $argl - (long) ???
	    # $argp - (pointer) ???
	    # $new_func - function pointer ??? (CRYPTO_EX_new *)
	    # $dup_func - function pointer ??? (CRYPTO_EX_dup *)
	    # $free_func - function pointer ??? (CRYPTO_EX_free *)
	    #
	    # returns: (integer) ???

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_get_ex_new_index.html>

       o   get_fd

	   Returns the file descriptor which is linked to $ssl.

	    my $rv = Net::SSLeay::get_fd($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: file descriptor (>=0) or -1 on failure

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_get_fd.html>

       o   get_finished

	   Obtains the latest 'Finished' message sent to the peer.

	   ??? (does this function really work?)

	    my $rv = Net::SSLeay::get_finished($ssl, $buf, $count);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $buf - buffer where the returned data will be stored (pointer ???, pre-allocated ???)
	    # $count - max. size of return data
	    #
	    # returns: actual size of the returned data in $buf

       o   get_peer_finished

	   Obtains the latest 'Finished' message expected from the peer.

	   ??? (does this function really work?)

	    my $rv = Net::SSLeay::get_peer_finished($ssl, $buf, $count);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $buf - buffer where the returned data will be stored (pointer ???, pre-allocated ???)
	    # $count - max. size of the return data
	    #
	    # returns: actual size of the returned data in $buf

       o   get_keyblock_size

	   NOTE: Does not exactly correspond to any low level API function.

	   ??? (more info needed)

	    my $rv = Net::SSLeay::get_keyblock_size($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: keyblock size, -1 on error

       o   get_mode

	   Returns the mode (bitmask) set for $ssl.

	    my $rv = Net::SSLeay::get_mode($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: mode (bitmask)

	   To decode the return value (bitmask) see documentation for "CTX_get_mode".

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_mode.html>

       o   set_mode

	   Adds the mode set via bitmask in $mode to $ssl. Options already set before are not
	   cleared.

	    my $rv = Net::SSLeay::set_mode($ssl, $mode);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $mode - mode (bitmask)
	    #
	    # returns: the new mode bitmask after adding $mode

	   For $mode bitmask details see "CTX_get_mode".

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_mode.html>

       o   get_options

	   Returns the options (bitmask) set for $ssl.

	    my $rv = Net::SSLeay::get_options($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: options (bitmask)

	   To decode the return value (bitmask) see documentation for "CTX_get_options".

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_options.html>

       o   set_options

	   Adds the options set via bitmask in $options to $ssl. Options already set before are
	   not cleared!

	    Net::SSLeay::set_options($ssl, $options);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $options - options (bitmask)
	    #
	    # returns: the new options bitmask after adding $options

	   For $options bitmask details see "CTX_get_options".

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_options.html>

       o   get_peer_certificate

	   Get the X509 certificate of the peer.

	    my $rv = Net::SSLeay::get_peer_certificate($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: value corresponding to openssl's X509 structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_get_peer_certificate.html>

       o   get_quiet_shutdown

	   Returns the 'quiet shutdown' setting of ssl.

	    my $rv = Net::SSLeay::get_quiet_shutdown($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: (integer) current 'quiet shutdown' value

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_quiet_shutdown.html>

       o   get_rbio

	   Get 'read' BIO linked to an SSL object $ssl.

	    my $rv = Net::SSLeay::get_rbio($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: value corresponding to openssl's BIO structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_get_rbio.html>

       o   get_read_ahead

	    my $rv = Net::SSLeay::get_read_ahead($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: (integer) read_ahead value

       o   set_read_ahead

	    Net::SSLeay::set_read_ahead($ssl, $val);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $val - read_ahead value to be set
	    #
	    # returns: the original read_ahead value

       o   get_server_random

	   Returns internal SSLv3 server_random value.

	    Net::SSLeay::get_server_random($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: server_random value (binary data)

       o   get_client_random

	   NOTE: Does not exactly correspond to any low level API function

	   Returns internal SSLv3 client_random value.

	    Net::SSLeay::get_client_random($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: client_random value (binary data)

       o   export_keying_material

	   Returns a buffer of $req_len bytes of keying material based on the constant string
	   $label using the masterkey and client and server random strings as described in
	   draft-ietf-pppext-eap-ttls-01.txt and See rfc2716 If p is present, it will be
	   concatenated before generating the keying material Returns undef on error

	       my $out = Net::SSLeay::export_keying_material($ssl, $req_len, $label, $p);

       o   get_session

	   Retrieve TLS/SSL session data used in $ssl. The reference count of the SSL_SESSION is
	   NOT incremented.

	    my $rv = Net::SSLeay::get_session($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: value corresponding to openssl's SSL_SESSION structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_get_session.html>

       o   SSL_get0_session

	   The alias for "get_session" (note that the name is "SSL_get0_session" NOT
	   "get0_session").

	    my $rv = Net::SSLeay::SSL_get0_session();

       o   get1_session

	   Returns a pointer to the SSL_SESSION actually used in $ssl. The reference count of the
	   SSL_SESSION is incremented by 1.

	    my $rv = Net::SSLeay::get1_session($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: value corresponding to openssl's SSL_SESSION structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_get_session.html>

       o   get_shared_ciphers

	   Returns string with a list (colon ':' separated) of ciphers shared between client and
	   server within SSL session $ssl.

	    my $rv = Net::SSLeay::get_shared_ciphers()
	    #
	    # returns: string like 'ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-AES256-SHA:DHE-RSA-AES256-SHA:DHE-DSS-AES256-SHA:...'

       o   get_shutdown

	   Returns the shutdown mode of $ssl.

	    my $rv = Net::SSLeay::get_shutdown($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: shutdown mode (bitmask) of ssl

	    #to decode the return value (bitmask) use:
	    0 - No shutdown setting, yet
	    1 - SSL_SENT_SHUTDOWN
	    2 - SSL_RECEIVED_SHUTDOWN

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_set_shutdown.html>

       o   get_ssl_method

	   Returns a function pointer to the TLS/SSL method set in $ssl.

	    my $rv = Net::SSLeay::get_ssl_method($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: value corresponding to openssl's SSL_METHOD structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_ssl_version.html>

       o   get_state

	   Returns the SSL connection state.

	    my $rv = Net::SSLeay::get_state($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: (integer) state value
	    #	       to decode the returned state check:
	    #	       SSL_ST_* constants in openssl/ssl.h
	    #	       SSL2_ST_* constants in openssl/ssl2.h
	    #	       SSL23_ST_* constants in openssl/ssl23.h
	    #	       SSL3_ST_* + DTLS1_ST_* constants in openssl/ssl3.h

       o   state

	   Exactly the same as "get_state".

	    my $rv = Net::SSLeay::state($ssl);

       o   get_verify_depth

	   Returns the verification depth limit currently set in $ssl.

	    my $rv = Net::SSLeay::get_verify_depth($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: current depth or -1 if no limit has been explicitly set

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_get_verify_mode.html>

       o   set_verify_depth

	   Sets the maximum depth for the certificate chain verification that shall be allowed
	   for $ssl.

	    Net::SSLeay::set_verify_depth($ssl, $depth);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $depth - (integer) depth
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_verify.html>

       o   get_verify_mode

	   Returns the verification mode (bitmask) currently set in $ssl.

	    my $rv = Net::SSLeay::get_verify_mode($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: mode (bitmask)

	   To decode the return value (bitmask) see documentation for "CTX_get_verify_mode".

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_get_verify_mode.html>

       o   set_verify

	   Sets the verification flags for $ssl to be $mode and specifies the $verify_callback
	   function to be used.

	    Net::SSLeay::set_verify($ssl, $mode, $callback);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $mode - mode (bitmask)
	    # $callback - [optional] reference to perl callback function
	    #
	    # returns: no return value

	   For $mode bitmask details see "CTX_get_verify_mode".

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_verify.html>

       o   get_verify_result

	   Returns the result of the verification of the X509 certificate presented by the peer,
	   if any.

	    my $rv = Net::SSLeay::get_verify_result($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: (integer)
	    #	   0 - X509_V_OK: ok
	    #	   2 - X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT: unable to get issuer certificate
	    #	   3 - X509_V_ERR_UNABLE_TO_GET_CRL: unable to get certificate CRL
	    #	   4 - X509_V_ERR_UNABLE_TO_DECRYPT_CERT_SIGNATURE: unable to decrypt certificate's signature
	    #	   5 - X509_V_ERR_UNABLE_TO_DECRYPT_CRL_SIGNATURE: unable to decrypt CRL's signature
	    #	   6 - X509_V_ERR_UNABLE_TO_DECODE_ISSUER_PUBLIC_KEY: unable to decode issuer public key
	    #	   7 - X509_V_ERR_CERT_SIGNATURE_FAILURE: certificate signature failure
	    #	   8 - X509_V_ERR_CRL_SIGNATURE_FAILURE: CRL signature failure
	    #	   9 - X509_V_ERR_CERT_NOT_YET_VALID: certificate is not yet valid
	    #	  10 - X509_V_ERR_CERT_HAS_EXPIRED: certificate has expired
	    #	  11 - X509_V_ERR_CRL_NOT_YET_VALID: CRL is not yet valid
	    #	  12 - X509_V_ERR_CRL_HAS_EXPIRED: CRL has expired
	    #	  13 - X509_V_ERR_ERROR_IN_CERT_NOT_BEFORE_FIELD: format error in certificate's notBefore field
	    #	  14 - X509_V_ERR_ERROR_IN_CERT_NOT_AFTER_FIELD: format error in certificate's notAfter field
	    #	  15 - X509_V_ERR_ERROR_IN_CRL_LAST_UPDATE_FIELD: format error in CRL's lastUpdate field
	    #	  16 - X509_V_ERR_ERROR_IN_CRL_NEXT_UPDATE_FIELD: format error in CRL's nextUpdate field
	    #	  17 - X509_V_ERR_OUT_OF_MEM: out of memory
	    #	  18 - X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT: self signed certificate
	    #	  19 - X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN: self signed certificate in certificate chain
	    #	  20 - X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY: unable to get local issuer certificate
	    #	  21 - X509_V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE: unable to verify the first certificate
	    #	  22 - X509_V_ERR_CERT_CHAIN_TOO_LONG: certificate chain too long
	    #	  23 - X509_V_ERR_CERT_REVOKED: certificate revoked
	    #	  24 - X509_V_ERR_INVALID_CA: invalid CA certificate
	    #	  25 - X509_V_ERR_PATH_LENGTH_EXCEEDED: path length constraint exceeded
	    #	  26 - X509_V_ERR_INVALID_PURPOSE: unsupported certificate purpose
	    #	  27 - X509_V_ERR_CERT_UNTRUSTED: certificate not trusted
	    #	  28 - X509_V_ERR_CERT_REJECTED: certificate rejected
	    #	  29 - X509_V_ERR_SUBJECT_ISSUER_MISMATCH: subject issuer mismatch
	    #	  30 - X509_V_ERR_AKID_SKID_MISMATCH: authority and subject key identifier mismatch
	    #	  31 - X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH: authority and issuer serial number mismatch
	    #	  32 - X509_V_ERR_KEYUSAGE_NO_CERTSIGN:key usage does not include certificate signing
	    #	  50 - X509_V_ERR_APPLICATION_VERIFICATION: application verification failure

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_get_verify_result.html>

       o   set_verify_result

	   Override result of peer certificate verification.

	    Net::SSLeay::set_verify_result($ssl, $v);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $v - (integer) result value
	    #
	    # returns: no return value

	   For more info about valid return values see "get_verify_result"

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_set_verify_result.html>

       o   get_wbio

	   Get 'write' BIO linked to an SSL object $ssl.

	    my $rv = Net::SSLeay::get_wbio($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: value corresponding to openssl's BIO structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_get_rbio.html>

       o   load_client_CA_file

	   Load X509 certificates from file (PEM formated).

	    my $rv = Net::SSLeay::load_client_CA_file($file);
	    # $file - (string) file name
	    #
	    # returns: value corresponding to openssl's STACK_OF(X509_NAME) structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_load_client_CA_file.html>

       o   clear_num_renegotiations

	   Executes SSL_CTRL_CLEAR_NUM_RENEGOTIATIONS command on $ssl.

	    my $rv = Net::SSLeay::clear_num_renegotiations($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: command result

       o   need_tmp_RSA

	   Executes SSL_CTRL_NEED_TMP_RSA command on $ssl.

	    my $rv = Net::SSLeay::need_tmp_RSA($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: command result

       o   num_renegotiations

	   Executes SSL_CTRL_GET_NUM_RENEGOTIATIONS command on $ssl.

	    my $rv = Net::SSLeay::num_renegotiations($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: command result

       o   total_renegotiations

	   Executes SSL_CTRL_GET_TOTAL_RENEGOTIATIONS command on $ssl.

	    my $rv = Net::SSLeay::total_renegotiations($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: command result

       o   peek

	   Copies $max bytes from the specified $ssl into the returned value.  In constrast to
	   the "Net::SSLeay::read()" function, the data in the SSL buffer is unmodified after the
	   SSL_peek() operation.

	    Net::SSLeay::peek($ssl, $max);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $max - [optional] max bytes to peek (integer) - default is 32768
	    #
	    # returns: read data, undef on error

       o   pending

	   Obtain number of readable bytes buffered in $ssl object.

	    my $rv = Net::SSLeay::pending($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: the number of bytes pending

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_pending.html>

       o   read

	   Tries to read $max bytes from the specified $ssl.

	    my $got = Net::SSLeay::read($ssl, $max);
	    my($got, $rv) = Net::SSLeay::read($ssl, $max);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $max - [optional] max bytes to read (integer) - default is 32768
	    #
	    # returns:
	    # in scalar context: data read from the TLS/SSL connection, undef on error
	    # in list context:	 two-item array consisting of data read (undef on error),
	    #			   and return code from SSL_read().

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_read.html>

       o   renegotiate

	   Turn on flags for renegotiation so that renegotiation will happen

	    my $rv = Net::SSLeay::renegotiate($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: 1 on success, 0 on failure

       o   rstate_string

	   Returns a 2 letter string indicating the current read state of the SSL object $ssl.

	    my $rv = Net::SSLeay::rstate_string($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: 2-letter string

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_rstate_string.html>

       o   rstate_string_long

	   Returns a string indicating the current read state of the SSL object ssl.

	    my $rv = Net::SSLeay::rstate_string_long($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: string with current state

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_rstate_string.html>

       o   session_reused

	   Query whether a reused session was negotiated during handshake.

	    my $rv = Net::SSLeay::session_reused($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: 0 - new session was negotiated; 1 - session was reused.

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_session_reused.html>

       o   set1_param

	   Applies X509 verification parameters $vpm on $ssl

	    my $rv = Net::SSLeay::set1_param($ssl, $vpm);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $vpm - value corresponding to openssl's X509_VERIFY_PARAM structure
	    #
	    # returns: 1 on success, 0 on failure

       o   set_accept_state

	   Sets $ssl to work in server mode.

	    Net::SSLeay::set_accept_state($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_set_connect_state.html>

       o   set_bio

	   Connects the BIOs $rbio and $wbio for the read and write operations of the TLS/SSL
	   (encrypted) side of $ssl.

	    Net::SSLeay::set_bio($ssl, $rbio, $wbio);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $rbio - value corresponding to openssl's BIO structure
	    # $wbio - value corresponding to openssl's BIO structure
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_set_bio.html>

       o   set_cipher_list

	   Sets the list of ciphers only for ssl.

	    my $rv = Net::SSLeay::set_cipher_list($ssl, $str);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $str - (string) cipher list e.g. '3DES:+RSA'
	    #
	    # returns: 1 if any cipher could be selected and 0 on complete failure

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_cipher_list.html>

       o   set_client_CA_list

	   Sets the list of CAs sent to the client when requesting a client certificate for the
	   chosen $ssl, overriding the setting valid for $ssl's SSL_CTX object.

	    my $rv = Net::SSLeay::set_client_CA_list($ssl, $list);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $list - value corresponding to openssl's STACK_OF(X509_NAME) structure
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_client_CA_list.html>

       o   set_connect_state

	   Sets $ssl to work in client mode.

	    Net::SSLeay::set_connect_state($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_set_connect_state.html>

       o   set_fd

	   Sets the file descriptor $fd as the input/output facility for the TLS/SSL (encrypted)
	   side of $ssl, $fd will typically be the socket file descriptor of a network
	   connection.

	    my $rv = Net::SSLeay::set_fd($ssl, $fd);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $fd - (integer) file handle (got via perl's fileno)
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_set_fd.html>

       o   set_rfd

	   Sets the file descriptor $fd as the input (read) facility for the TLS/SSL (encrypted)
	   side of $ssl.

	    my $rv = Net::SSLeay::set_rfd($ssl, $fd);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $fd - (integer) file handle (got via perl's fileno)
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_set_fd.html>

       o   set_wfd

	    my $rv = Net::SSLeay::set_wfd($ssl, $fd);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $fd - (integer) file handle (got via perl's fileno)
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_set_fd.html>

       o   set_info_callback

	   Sets the callback function, that can be used to obtain state information for $ssl
	   during connection setup and use.  When callback is 0 (NULL), the callback setting
	   currently valid for ctx is used.

	   ??? (does this function really work?)

	    Net::SSLeay::set_info_callback($ssl, $cb);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $cb - pointer to function ???
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_info_callback.html>

       o   set_pref_cipher

	   Sets the list of available ciphers for $ssl using the control string $str.

	    my $rv = Net::SSLeay::set_pref_cipher($ssl, $str);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $str - (string) cipher list e.g. '3DES:+RSA'
	    #
	    # returns: 1 if any cipher could be selected and 0 on complete failure

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_cipher_list.html>

       o   set_purpose

	    my $rv = Net::SSLeay::set_purpose($ssl, $purpose);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $purpose - (integer) purpose identifier
	    #
	    # returns: 1 on success, 0 on failure

	   For more info about available $purpose identifiers see "CTX_set_purpose".

       o   set_quiet_shutdown

	   Sets the 'quiet shutdown' flag for $ssl to be $mode.

	    Net::SSLeay::set_quiet_shutdown($ssl, $mode);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $mode - 0 or 1
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_quiet_shutdown.html>

       o   set_session

	   Set a TLS/SSL session to be used during TLS/SSL connect.

	    my $rv = Net::SSLeay::set_session($to, $ses);
	    # $to - value corresponding to openssl's SSL structure
	    # $ses - value corresponding to openssl's SSL_SESSION structure
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_set_session.html>

       o   set_session_id_context

	   Sets the context $sid_ctx of length $sid_ctx_len within which a session can be reused
	   for the $ssl object.

	    my $rv = Net::SSLeay::set_session_id_context($ssl, $sid_ctx, $sid_ctx_len);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $sid_ctx - data buffer
	    # $sid_ctx_len - length of data in $sid_ctx
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_CTX_set_session_id_context.html>

       o   set_session_secret_cb

	   Setup pre-shared secret session resumption function.

	    Net::SSLeay::set_session_secret_cb($ssl, $func, $data);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $func - perl reference to callback function
	    # $data - [optional] data that will be passed to callback function when invoked
	    #
	    # returns: no return value

       o   set_shutdown

	   Sets the shutdown state of $ssl to $mode.

	    Net::SSLeay::set_shutdown($ssl, $mode);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $mode - (integer) shutdown mode:
	    #	      0 - No shutdown
	    #	      1 - SSL_SENT_SHUTDOWN
	    #	      2 - SSL_RECEIVED_SHUTDOWN
	    #	      3 - SSL_RECEIVED_SHUTDOWN+SSL_SENT_SHUTDOWN
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_set_shutdown.html>

       o   set_ssl_method

	   Sets a new TLS/SSL method for a particular $ssl object.

	    my $rv = Net::SSLeay::set_ssl_method($ssl, $method);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $method - value corresponding to openssl's SSL_METHOD structure
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_ssl_version.html>

       o   set_tmp_dh

	   Sets DH parameters to be used to be $dh.

	    my $rv = Net::SSLeay::set_tmp_dh($ssl, $dh);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $dh - value corresponding to openssl's DH structure
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_tmp_dh_callback.html>

       o   set_tmp_dh_callback

	   Sets the callback function for $ssl to be used when a DH parameters are required to
	   $dh_cb.

	   ??? (does this function really work?)

	    Net::SSLeay::set_tmp_dh_callback($ssl, $dh);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $dh_cb - pointer to function ???
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_tmp_dh_callback.html>

       o   set_tmp_rsa

	   Sets the temporary/ephemeral RSA key to be used in $ssl to be $rsa.

	    my $rv = Net::SSLeay::set_tmp_rsa($ssl, $rsa);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $rsa - value corresponding to openssl's RSA structure
	    #
	    # returns: 1 on success, 0 on failure

	   Example:

	    $rsakey = Net::SSLeay::RSA_generate_key();
	    Net::SSLeay::set_tmp_rsa($ssl, $rsakey);
	    Net::SSLeay::RSA_free($rsakey);

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_tmp_rsa_callback.html>

       o   set_tmp_rsa_callback

	   Sets the callback function for $ssl to be used when a temporary/ephemeral RSA key is
	   required to $tmp_rsa_callback.

	   ??? (does this function really work?)

	    Net::SSLeay::set_tmp_rsa_callback($ssl, $tmp_rsa_callback);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $tmp_rsa_callback - (function pointer) ???
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_set_tmp_rsa_callback.html>

       o   set_trust

	    my $rv = Net::SSLeay::set_trust($ssl, $trust);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $trust - (integer) trust identifier
	    #
	    # returns: the original value

	   For more details about $trust values see "CTX_set_trust".

       o   shutdown

	   Shuts down an active TLS/SSL connection. It sends the 'close notify' shutdown alert to
	   the peer.

	    my $rv = Net::SSLeay::shutdown($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: 1 - shutdown was successfully completed
	    #	       0 - shutdown is not yet finished,
	    #	      -1 - shutdown was not successful

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_shutdown.html>

       o   state_string

	   Returns a 6 letter string indicating the current state of the SSL object $ssl.

	    my $rv = Net::SSLeay::state_string($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: 6-letter string

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_state_string.html>

       o   state_string_long

	   Returns a string indicating the current state of the SSL object $ssl.

	    my $rv = Net::SSLeay::state_string_long($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: state strings

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_state_string.html>

       o   use_PrivateKey

	   Adds $pkey as private key to $ssl.

	    my $rv = Net::SSLeay::use_PrivateKey($ssl, $pkey);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $pkey - value corresponding to openssl's EVP_PKEY structure
	    #
	    # returns: 1 on success, otherwise check out the error stack to find out the reason

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_use_certificate.html>

       o   use_PrivateKey_ASN1

	   Adds the private key of type $pk stored in $data to $ssl.

	    my $rv = Net::SSLeay::use_PrivateKey_ASN1($pk, $ssl, $d, $len);
	    # $pk - (integer) key type, NID of corresponding algorithm
	    # $ssl - value corresponding to openssl's SSL structure
	    # $data - key data (binary)
	    # $len - length of $data
	    #
	    # returns: 1 on success, otherwise check out the error stack to find out the reason

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_use_certificate.html>

       o   use_PrivateKey_file

	   Adds the first private key found in $file to $ssl.

	    my $rv = Net::SSLeay::use_PrivateKey_file($ssl, $file, $type);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $file - (string) file name
	    # $type - (integer) type - use constants &Net::SSLeay::FILETYPE_PEM or &Net::SSLeay::FILETYPE_ASN1
	    #
	    # returns: 1 on success, otherwise check out the error stack to find out the reason

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_use_certificate.html>

       o   use_RSAPrivateKey

	   Adds $rsa as RSA private key to $ssl.

	    my $rv = Net::SSLeay::use_RSAPrivateKey($ssl, $rsa);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $rsa - value corresponding to openssl's RSA structure
	    #
	    # returns: 1 on success, otherwise check out the error stack to find out the reason

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_use_certificate.html>

       o   use_RSAPrivateKey_ASN1

	   Adds RSA private key stored in $data to $ssl.

	    my $rv = Net::SSLeay::use_RSAPrivateKey_ASN1($ssl, $data, $len);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $data - key data (binary)
	    # $len - length of $data
	    #
	    # returns: 1 on success, otherwise check out the error stack to find out the reason

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_use_certificate.html>

       o   use_RSAPrivateKey_file

	   Adds the first RSA private key found in $file to $ssl.

	    my $rv = Net::SSLeay::use_RSAPrivateKey_file($ssl, $file, $type);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $file - (string) file name
	    # $type - (integer) type - use constants &Net::SSLeay::FILETYPE_PEM or &Net::SSLeay::FILETYPE_ASN1
	    #
	    # returns: 1 on success, otherwise check out the error stack to find out the reason

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_use_certificate.html>

       o   use_certificate

	   Loads the certificate $x into $ssl.

	    my $rv = Net::SSLeay::use_certificate($ssl, $x);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $x - value corresponding to openssl's X509 structure
	    #
	    # returns: 1 on success, otherwise check out the error stack to find out the reason

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_use_certificate.html>

       o   use_certificate_ASN1

	   Loads the ASN1 encoded certificate from $data to $ssl.

	    my $rv = Net::SSLeay::use_certificate_ASN1($ssl, $data, $len);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $data - certificate data (binary)
	    # $len - length of $data
	    #
	    # returns: 1 on success, otherwise check out the error stack to find out the reason

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_use_certificate.html>

       o   use_certificate_file

	   Loads the first certificate stored in $file into $ssl.

	    my $rv = Net::SSLeay::use_certificate_file($ssl, $file, $type);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $file - (string) file name
	    # $type - (integer) type - use constants &Net::SSLeay::FILETYPE_PEM or &Net::SSLeay::FILETYPE_ASN1
	    #
	    # returns: 1 on success, otherwise check out the error stack to find out the reason

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CTX_use_certificate.html>

       o   version

	   Returns SSL/TLS protocol version

	    my $rv = Net::SSLeay::version($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: (integer) protocol version
	    #	       0x0002 - SSL2_VERSION  (SSLv2)
	    #	       0x0300 - SSL3_VERSION  (SSLv3)
	    #	       0x0301 - TLS1_VERSION  (TLSv1)
	    #	       0xFEFF - DTLS1_VERSION (DTLSv1)

       o   want

	   Returns state information for the SSL object $ssl.

	    my $rv = Net::SSLeay::want($ssl);
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: state
	    #	       1 - SSL_NOTHING
	    #	       2 - SSL_WRITING
	    #	       3 - SSL_READING
	    #	       4 - SSL_X509_LOOKUP

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_want.html>

       o   write

	   Writes data from the buffer $data into the specified $ssl connection.

	    my $rv = Net::SSLeay::write($ssl, $data);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $data - data to be written
	    #
	    # returns: >0 - (success) number of bytes actually written to the TLS/SSL connection
	    #		0 - write not successful, probably the underlying connection was closed
	    #	       <0 - error

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_write.html>

       o   write_partial

	   NOTE: Does not exactly correspond to any low level API function

	   Writes a fragment of data data from the buffer $data into the specified $ssl
	   connection.

	    my $rv = Net::SSLeay::write_partial($ssl, $from, $count, $data);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $from - (integer) offset from the beginning of $data
	    # $count - (integer) length of data to be written
	    # $data - data buffer
	    #
	    # returns: >0 - (success) number of bytes actually written to the TLS/SSL connection
	    #		0 - write not successful, probably the underlying connection was closed
	    #	       <0 - error

       o   set_tlsext_host_name

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before; requires at least
	   openssl-0.9.8f

	   Sets TLS servername extension on SLL object $ssl to value $name.

	    my $rv = set_tlsext_host_name($ssl, $name);
	    # $ssl - value corresponding to openssl's SSL structure
	    # $name - (string) name to be set
	    #
	    # returns: 1 on success, 0 on failure

       Low level API: RAND_* related functions

       Check openssl doc related to RAND stuff <http://www.openssl.org/docs/crypto/rand.html>

       o   RAND_add

	   Mixes the $num bytes at $buf into the PRNG state.

	    Net::SSLeay::RAND_add($buf, $num, $entropy);
	    # $buf - buffer with data to be mixed into the PRNG state
	    # $num - number of bytes in $buf
	    # $entropy - estimate of how much randomness is contained in $buf (in bytes)
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/crypto/RAND_add.html>

       o   RAND_seed

	   Equivalent to "RAND_add" when $num == $entropy.

	    Net::SSLeay::RAND_seed($buf);   # Perlishly figures out buf size
	    # $buf - buffer with data to be mixed into the PRNG state
	    # $num - number of bytes in $buf
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/crypto/RAND_add.html>

       o   RAND_status

	   Gives PRNG status (seeded enough or not).

	    my $rv = Net::SSLeay::RAND_status();
	    #returns: 1 if the PRNG has been seeded with enough data, 0 otherwise

	   Check openssl doc <http://www.openssl.org/docs/crypto/RAND_add.html>

       o   RAND_bytes

	   Puts $num cryptographically strong pseudo-random bytes into $buf.

	    my $rv = Net::SSLeay::RAND_bytes($buf, $num);
	    # $buf - buffer where the random data will be stored
	    # $num - the size (in bytes) of requested random data
	    #
	    # returns: 1 on success, 0 otherwise

	   Check openssl doc <http://www.openssl.org/docs/crypto/RAND_bytes.html>

       o   RAND_pseudo_bytes

	   Puts $num pseudo-random (not necessarily unpredictable) bytes into $buf.

	    my $rv = Net::SSLeay::RAND_pseudo_bytes($buf, $num);
	    # $buf - buffer where the random data will be stored
	    # $num - the size (in bytes) of requested random data
	    #
	    # returns: 1 if the bytes generated are cryptographically strong, 0 otherwise

	   Check openssl doc <http://www.openssl.org/docs/crypto/RAND_bytes.html>

       o   RAND_cleanup

	   Erase the PRNG state.

	    Net::SSLeay::RAND_cleanup();
	    # no args, no return value

	   Check openssl doc <http://www.openssl.org/docs/crypto/RAND_cleanup.html>

       o   RAND_egd

	   Queries the entropy gathering daemon EGD on socket $path for 255 bytes.

	    my $rv = Net::SSLeay::RAND_egd($path);
	    # $path - path to a socket of entropy gathering daemon EGD
	    #
	    # returns: the number of bytes read from the daemon on success, and -1 on failure

	   Check openssl doc <http://www.openssl.org/docs/crypto/RAND_egd.html>

       o   RAND_egd_bytes

	   Queries the entropy gathering daemon EGD on socket $path for $bytes bytes.

	    my $rv = Net::SSLeay::RAND_egd_bytes($path, $bytes);
	    # $path - path to a socket of entropy gathering daemon EGD
	    # $bytes - number of bytes we want from EGD
	    #
	    # returns: the number of bytes read from the daemon on success, and -1 on failure

	   Check openssl doc <http://www.openssl.org/docs/crypto/RAND_egd.html>

       o   RAND_file_name

	   Generates a default path for the random seed file.

	    my $file = Net::SSLeay::RAND_file_name($num);
	    # $num - maximum size of returned file name
	    #
	    # returns: string with file name on success, '' (empty string) on failure

	   Check openssl doc <http://www.openssl.org/docs/crypto/RAND_load_file.html>

       o   RAND_load_file

	   Reads $max_bytes of bytes from $file_name and adds them to the PRNG.

	    my $rv = Net::SSLeay::RAND_load_file($file_name, $max_bytes);
	    # $file_name - the name of file
	    # $max_bytes - bytes to read from $file_name; -1 => the complete file is read
	    #
	    # returns: the number of bytes read

	   Check openssl doc <http://www.openssl.org/docs/crypto/RAND_load_file.html>

       o   RAND_write_file

	   Writes 1024 random bytes to $file_name which can be used to initialize the PRNG by
	   calling "RAND_load_file" in a later session.

	    my $rv = Net::SSLeay::RAND_write_file($file_name);
	    # $file_name - the name of file
	    #
	    # returns: the number of bytes written, and -1 if the bytes written were generated without appropriate seed

	   Check openssl doc <http://www.openssl.org/docs/crypto/RAND_load_file.html>

       o   RAND_poll

	   Collects some entropy from operating system and adds it to the PRNG.

	    my $rv = Net::SSLeay::RAND_poll();
	    # returns: 1 on success, 0 on failure (unable to gather reasonable entropy)

       Low level API: OBJ_* related functions

       o   OBJ_cmp

	   Compares ASN1_OBJECT $a to ASN1_OBJECT $b.

	    my $rv = Net::SSLeay::OBJ_cmp($a, $b);
	    # $a - value corresponding to openssl's ASN1_OBJECT structure
	    # $b - value corresponding to openssl's ASN1_OBJECT structure
	    #
	    # returns: if the two are identical 0 is returned

	   Check openssl doc <http://www.openssl.org/docs/crypto/OBJ_nid2obj.html>

       o   OBJ_dup

	   Returns a copy/duplicate of $o.

	    my $rv = Net::SSLeay::OBJ_dup($o);
	    # $o - value corresponding to openssl's ASN1_OBJECT structure
	    #
	    # returns: value corresponding to openssl's ASN1_OBJECT structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/crypto/OBJ_nid2obj.html>

       o   OBJ_nid2ln

	   Returns long name for given NID $n.

	    my $rv = Net::SSLeay::OBJ_nid2ln($n);
	    # $n - (integer) NID
	    #
	    # returns: (string) long name e.g. 'commonName'

	   Check openssl doc <http://www.openssl.org/docs/crypto/OBJ_nid2obj.html>

       o   OBJ_ln2nid

	   Returns NID corresponding to given long name $n.

	    my $rv = Net::SSLeay::OBJ_ln2nid($s);
	    # $s - (string) long name e.g. 'commonName'
	    #
	    # returns: (integer) NID

       o   OBJ_nid2sn

	   Returns short name for given NID $n.

	    my $rv = Net::SSLeay::OBJ_nid2sn($n);
	    # $n - (integer) NID
	    #
	    # returns: (string) short name e.g. 'CN'

	   Example:

	    print Net::SSLeay::OBJ_nid2sn(&Net::SSLeay::NID_commonName);

       o   OBJ_sn2nid

	   Returns NID corresponding to given short name $s.

	    my $rv = Net::SSLeay::OBJ_sn2nid($s);
	    # $s - (string) short name e.g. 'CN'
	    #
	    # returns: (integer) NID

	   Example:

	    print "NID_commonName constant=", &Net::SSLeay::NID_commonName;
	    print "OBJ_sn2nid('CN')=", Net::SSLeay::OBJ_sn2nid('CN');

       o   OBJ_nid2obj

	   Returns ASN1_OBJECT for given NID $n.

	    my $rv = Net::SSLeay::OBJ_nid2obj($n);
	    # $n - (integer) NID
	    #
	    # returns: value corresponding to openssl's ASN1_OBJECT structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/crypto/OBJ_nid2obj.html>

       o   OBJ_obj2nid

	   Returns NID corresponding to given ASN1_OBJECT $o.

	    my $rv = Net::SSLeay::OBJ_obj2nid($o);
	    # $o - value corresponding to openssl's ASN1_OBJECT structure
	    #
	    # returns: (integer) NID

	   Check openssl doc <http://www.openssl.org/docs/crypto/OBJ_nid2obj.html>

       o   OBJ_txt2obj

	   Converts the text string s into an ASN1_OBJECT structure. If $no_name is 0 then long
	   names (e.g. 'commonName') and short names (e.g. 'CN') will be interpreted as well as
	   numerical forms (e.g. '2.5.4.3'). If $no_name is 1 only the numerical form is
	   acceptable.

	    my $rv = Net::SSLeay::OBJ_txt2obj($s, $no_name);
	    # $s - text string to be converted
	    # $no_name - (integer) 0 or 1
	    #
	    # returns: value corresponding to openssl's ASN1_OBJECT structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/crypto/OBJ_nid2obj.html>

       o   OBJ_obj2txt

	   Converts the ASN1_OBJECT a into a textual representation.

	    Net::SSLeay::OBJ_obj2txt($a, $no_name);
	    # $a - value corresponding to openssl's ASN1_OBJECT structure
	    # $no_name - (integer) 0 or 1
	    #
	    # returns: textual representation e.g. 'commonName' ($no_name=0), '2.5.4.3' ($no_name=1)

	   Check openssl doc <http://www.openssl.org/docs/crypto/OBJ_nid2obj.html>

       o   OBJ_txt2nid

	   Returns NID corresponding to text string $s which can be a long name, a short name or
	   the numerical respresentation of an object.

	    my $rv = Net::SSLeay::OBJ_txt2nid($s);
	    # $s - (string) e.g. 'commonName' or 'CN' or '2.5.4.3'
	    #
	    # returns: (integer) NID

	   Example:

	    my $nid = Net::SSLeay::OBJ_txt2nid('2.5.4.3');
	    Net::SSLeay::OBJ_nid2sn($n);

	   Check openssl doc <http://www.openssl.org/docs/crypto/OBJ_nid2obj.html>

       Low level API: ASN1_INTEGER_* related functions

       o   ASN1_INTEGER_new

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Creates a new ASN1_INTEGER structure.

	    my $rv = Net::SSLeay::ASN1_INTEGER_new();
	    #
	    # returns: value corresponding to openssl's ASN1_INTEGER structure (0 on failure)

       o   ASN1_INTEGER_free

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Free an allocated ASN1_INTEGER structure.

	    Net::SSLeay::ASN1_INTEGER_free($i);
	    # $i - value corresponding to openssl's ASN1_INTEGER structure
	    #
	    # returns: no return value

       o   ASN1_INTEGER_get

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Returns integer value of given ASN1_INTEGER object.

	   BEWARE: If the value stored in ASN1_INTEGER is greater than max. integer that can be
	   stored in 'long' type (usually 32bit but may vary according to platform) then this
	   function will return -1.  For getting large ASN1_INTEGER values consider using
	   "P_ASN1_INTEGER_get_dec" or "P_ASN1_INTEGER_get_hex".

	    my $rv = Net::SSLeay::ASN1_INTEGER_get($a);
	    # $a - value corresponding to openssl's ASN1_INTEGER structure
	    #
	    # returns: integer value of ASN1_INTEGER object in $a

       o   ASN1_INTEGER_set

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Sets value of given ASN1_INTEGER object to value $val

	   BEWARE: $val has max. limit (= max. integer that can be stored in 'long' type).  For
	   setting large ASN1_INTEGER values consider using "P_ASN1_INTEGER_set_dec" or
	   "P_ASN1_INTEGER_set_hex".

	    my $rv = Net::SSLeay::ASN1_INTEGER_set($i, $val);
	    # $i - value corresponding to openssl's ASN1_INTEGER structure
	    # $val - integer value
	    #
	    # returns: 1 on success, 0 on failure

       o   P_ASN1_INTEGER_get_dec

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Returns string with decimal representation of integer value of given ASN1_INTEGER
	   object.

	    Net::SSLeay::P_ASN1_INTEGER_get_dec($i);
	    # $i - value corresponding to openssl's ASN1_INTEGER structure
	    #
	    # returns: string with decimal representation

       o   P_ASN1_INTEGER_get_hex

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Returns string with hexadecimal representation of integer value of given ASN1_INTEGER
	   object.

	    Net::SSLeay::P_ASN1_INTEGER_get_hex($i);
	    # $i - value corresponding to openssl's ASN1_INTEGER structure
	    #
	    # returns: string with hexadecimal representation

       o   P_ASN1_INTEGER_set_dec

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Sets value of given ASN1_INTEGER object to value $val (decimal string, suitable for
	   large integers)

	    Net::SSLeay::P_ASN1_INTEGER_set_dec($i, $str);
	    # $i - value corresponding to openssl's ASN1_INTEGER structure
	    # $str - string with decimal representation
	    #
	    # returns: 1 on success, 0 on failure

       o   P_ASN1_INTEGER_set_hex

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Sets value of given ASN1_INTEGER object to value $val (hexadecimal string, suitable
	   for large integers)

	    Net::SSLeay::P_ASN1_INTEGER_set_hex($i, $str);
	    # $i - value corresponding to openssl's ASN1_INTEGER structure
	    # $str - string with hexadecimal representation
	    #
	    # returns: 1 on success, 0 on failure

       Low level API: ASN1_STRING_* related functions

       o   P_ASN1_STRING_get

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Returns string value of given ASN1_STRING object.

	    Net::SSLeay::P_ASN1_STRING_get($s, $utf8_decode);
	    # $s - value corresponding to openssl's ASN1_STRING structure
	    # $utf8_decode - [optional] 0 or 1 whether the returned value should be utf8 decoded (default=0)
	    #
	    # returns: string

	    $string = Net::SSLeay::P_ASN1_STRING_get($s);
	    #is the same as:
	    $string = Net::SSLeay::P_ASN1_STRING_get($s, 0);

       Low level API: ASN1_TIME_* related functions

       o   ASN1_TIME_new

	   COMPATIBILITY: not available in Net-SSLeay-1.42 and before

	    my $time = ASN1_TIME_new();
	    # returns: value corresponding to openssl's ASN1_TIME structure

       o   ASN1_TIME_free

	   COMPATIBILITY: not available in Net-SSLeay-1.42 and before

	    ASN1_TIME_free($time);
	    # $time - value corresponding to openssl's ASN1_TIME structure

       o   ASN1_TIME_set

	   COMPATIBILITY: not available in Net-SSLeay-1.42 and before

	    ASN1_TIME_set($time, $t);
	    # $time - value corresponding to openssl's ASN1_TIME structure
	    # $t - time value in seconds since 1.1.1970

	   BEWARE: It is platform dependent how this function will handle dates after 2038.
	   Although perl's integer is large enough the internal implementation of this function
	   is dependent on the size of time_t structure (32bit time_t has problem with 2038).

	   If you want to safely set date and time after 2038 use function
	   "P_ASN1_TIME_set_isotime".

       o   P_ASN1_TIME_get_isotime

	   COMPATIBILITY: not available in Net-SSLeay-1.42 and before; requires at least
	   openssl-0.9.7e

	   NOTE: Does not exactly correspond to any low level API function

	   Gives ISO-8601 string representation of ASN1_TIME structure.

	    my $datetime_string = P_ASN1_TIME_get_isotime($time);
	    # $time - value corresponding to openssl's ASN1_TIME structure
	    #
	    # returns: datetime string like '2033-05-16T20:39:37Z' or '' on failure

	   The output format is compatible with module DateTime::Format::RFC3339

       o   P_ASN1_TIME_set_isotime

	   COMPATIBILITY: not available in Net-SSLeay-1.42 and before; requires at least
	   openssl-0.9.7e

	   NOTE: Does not exactly correspond to any low level API function

	   Sets time and date value of ANS1_time structure.

	    my $rv = P_ASN1_TIME_set_isotime($time, $string);
	    # $time - value corresponding to openssl's ASN1_TIME structure
	    # $string - ISO-8601 timedate string like '2033-05-16T20:39:37Z'
	    #
	    # returns: 1 on success, 0 on failure

	   The $string parameter has to be in full form like "2012-03-22T23:55:33" or
	   "2012-03-22T23:55:33Z" or "2012-03-22T23:55:33CET". Short forms like
	   "2012-03-22T23:55" or "2012-03-22" are not supported.

       o   P_ASN1_TIME_put2string

	   COMPATIBILITY: not available in Net-SSLeay-1.42 and before, has bugs with
	   openssl-0.9.8i

	   NOTE: Does not exactly correspond to any low level API function

	   Gives string representation of ASN1_TIME structure.

	    my $str = P_ASN1_TIME_put2string($time);
	    # $time - value corresponding to openssl's ASN1_TIME structure
	    #
	    # returns: datetime string like 'May 16 20:39:37 2033 GMT'

       o   P_ASN1_UTCTIME_put2string

	   NOTE: deprecated function, only for backward compatibility, just an alias for
	   "P_ASN1_TIME_put2string"

       Low level API: X509_* related functions

       o   X509_new

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Allocates and initializes a X509 structure.

	    my $rv = Net::SSLeay::X509_new();
	    #
	    # returns: value corresponding to openssl's X509 structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/crypto/X509_new.html>

       o   X509_free

	   Frees up the X509 structure.

	    Net::SSLeay::X509_free($a);
	    # $a - value corresponding to openssl's X509 structure
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/crypto/X509_new.html>

       o   X509_certificate_type

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Returns bitmask with type of certificate $x.

	    my $rv = Net::SSLeay::X509_certificate_type($x);
	    # $x - value corresponding to openssl's X509 structure
	    #
	    # returns: (integer) bitmask with certificate type

	    #to decode bitmask returned by this function use these constants:
	    &Net::SSLeay::EVP_PKS_DSA
	    &Net::SSLeay::EVP_PKS_EC
	    &Net::SSLeay::EVP_PKS_RSA
	    &Net::SSLeay::EVP_PKT_ENC
	    &Net::SSLeay::EVP_PKT_EXCH
	    &Net::SSLeay::EVP_PKT_EXP
	    &Net::SSLeay::EVP_PKT_SIGN
	    &Net::SSLeay::EVP_PK_DH
	    &Net::SSLeay::EVP_PK_DSA
	    &Net::SSLeay::EVP_PK_EC
	    &Net::SSLeay::EVP_PK_RSA

       o   X509_digest

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Computes digest/fingerprint of X509 $data using $type hash function.

	    my $digest_value = Net::SSLeay::X509_digest($data, $type);
	    # $data - value corresponding to openssl's X509 structure
	    # $type - value corresponding to openssl's EVP_MD structure - e.g. got via EVP_get_digestbyname()
	    #
	    # returns: hash value (binary)

	    #to get printable (hex) value of digest use:
	    print unpack('H*', $digest_value);

       o   X509_issuer_and_serial_hash

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Sort of a checksum of issuer name and serial number of X509 certificate $x.	The
	   result is not a full hash (e.g. sha-1), it is kind-of-a-hash truncated to the size of
	   'unsigned long' (32 bits).  The resulting value might differ across different openssl
	   versions for the same X509 certificate.

	    my $rv = Net::SSLeay::X509_issuer_and_serial_hash($x);
	    # $x - value corresponding to openssl's X509 structure
	    #
	    # returns: number representing checksum

       o   X509_issuer_name_hash

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Sort of a checksum of issuer name of X509 certificate $x.  The result is not a full
	   hash (e.g. sha-1), it is kind-of-a-hash truncated to the size of 'unsigned long' (32
	   bits).  The resulting value might differ across different openssl versions for the
	   same X509 certificate.

	    my $rv = Net::SSLeay::X509_issuer_name_hash($x);
	    # $x - value corresponding to openssl's X509 structure
	    #
	    # returns: number representing checksum

       o   X509_subject_name_hash

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Sort of a checksum of subject name of X509 certificate $x.  The result is not a full
	   hash (e.g. sha-1), it is kind-of-a-hash truncated to the size of 'unsigned long' (32
	   bits).  The resulting value might differ across different openssl versions for the
	   same X509 certificate.

	    my $rv = Net::SSLeay::X509_subject_name_hash($x);
	    # $x - value corresponding to openssl's X509 structure
	    #
	    # returns: number representing checksum

       o   X509_pubkey_digest

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before; requires at least
	   openssl-0.9.7

	   Computes digest/fingerprint of public key from X509 certificate $data using $type hash
	   function.

	    my $digest_value = Net::SSLeay::X509_pubkey_digest($data, $type);
	    # $data - value corresponding to openssl's X509 structure
	    # $type - value corresponding to openssl's EVP_MD structure - e.g. got via EVP_get_digestbyname()
	    #
	    # returns: hash value (binary)

	    #to get printable (hex) value of digest use:
	    print unpack('H*', $digest_value);

       o   X509_set_issuer_name

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Sets issuer of X509 certificate $x to $name.

	    my $rv = Net::SSLeay::X509_set_issuer_name($x, $name);
	    # $x - value corresponding to openssl's X509 structure
	    # $name - value corresponding to openssl's X509_NAME structure
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_set_pubkey

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Sets public key of X509 certificate $x to $pkey.

	    my $rv = Net::SSLeay::X509_set_pubkey($x, $pkey);
	    # $x - value corresponding to openssl's X509 structure
	    # $pkey - value corresponding to openssl's EVP_PKEY structure
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_set_serialNumber

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Sets serial number of X509 certificate $x to $serial.

	    my $rv = Net::SSLeay::X509_set_serialNumber($x, $serial);
	    # $x - value corresponding to openssl's X509 structure
	    # $serial - value corresponding to openssl's ASN1_INTEGER structure
	    #
	    # returns: 1 on success, 0 on failure

	    #to create $serial value use one of these:
	    $serial = Net::SSLeay::P_ASN1_INTEGER_set_hex('45ad6f');
	    $serial = Net::SSLeay::P_ASN1_INTEGER_set_dec('7896541238529631478');
	    $serial = Net::SSLeay::ASN1_INTEGER_set(45896);

       o   X509_set_subject_name

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Sets subject of X509 certificate $x to $name.

	    my $rv = Net::SSLeay::X509_set_subject_name($x, $name);
	    # $x - value corresponding to openssl's X509 structure
	    # $name - value corresponding to openssl's X509_NAME structure
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_set_version

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Set 'version' value for X509 certificate $ to $version.

	    my $rv = Net::SSLeay::X509_set_version($x, $version);
	    # $x - value corresponding to openssl's X509 structure
	    # $version - (integer) version number
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_sign

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Sign X509 certificate $x with private key $pkey (using digest algorithm $md).

	    my $rv = Net::SSLeay::X509_sign($x, $pkey, $md);
	    # $x - value corresponding to openssl's X509 structure
	    # $pkey - value corresponding to openssl's EVP_PKEY structure
	    # $md - value corresponding to openssl's EVP_MD structure
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_verify

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Verifies X509 object $a using public key $r (pubkey of issuing CA).

	    my $rv = Net::SSLeay::X509_verify($x, $r);
	    # $x - value corresponding to openssl's X509 structure
	    # $r - value corresponding to openssl's EVP_PKEY structure
	    #
	    # returns: 0 - verify failure, 1 - verify OK, <0 - error

       o   X509_get_ext_count

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Returns the total number of extensions in X509 object $x.

	    my $rv = Net::SSLeay::X509_get_ext_count($x);
	    # $x - value corresponding to openssl's X509 structure
	    #
	    # returns: count of extensions

       o   X509_get_pubkey

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Returns public key corresponding to given X509 object $x.

	    my $rv = Net::SSLeay::X509_get_pubkey($x);
	    # $x - value corresponding to openssl's X509 structure
	    #
	    # returns: value corresponding to openssl's EVP_PKEY structure (0 on failure)

       o   X509_get_serialNumber

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Returns serial number of X509 certificate $x.

	    my $rv = Net::SSLeay::X509_get_serialNumber($x);
	    # $x - value corresponding to openssl's X509 structure
	    #
	    # returns: value corresponding to openssl's ASN1_INTEGER structure (0 on failure)

	   See "P_ASN1_INTEGER_get_dec", "P_ASN1_INTEGER_get_hex" or "ASN1_INTEGER_get" to decode
	   ASN1_INTEGER object.

       o   X509_get_version

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Returns 'version' value of given X509 certificate $x.

	    my $rv = Net::SSLeay::X509_get_version($x);
	    # $x - value corresponding to openssl's X509 structure
	    #
	    # returns: (integer) version

       o   X509_get_ext

	   Returns X509_EXTENSION from $x509 based on given position/index.

	    my $rv = Net::SSLeay::X509_get_ext($x509, $index);
	    # $x509 - value corresponding to openssl's X509 structure
	    # $index - (integer) position/index of extension within $x509
	    #
	    # returns: value corresponding to openssl's X509_EXTENSION structure (0 on failure)

       o   X509_get_ext_by_NID

	   Returns X509_EXTENSION from $x509 based on given NID.

	    my $rv = Net::SSLeay::X509_get_ext_by_NID($x509, $nid, $loc);
	    # $x509 - value corresponding to openssl's X509 structure
	    # $nid - (integer) NID value
	    # $loc - (integer) position to start lookup at
	    #
	    # returns: position/index of extension, negative value on error
	    #	       call Net::SSLeay::X509_get_ext($x509, $rv) to get the actual extension

       o   X509_get_fingerprint

	   Returns fingerprint of certificate $cert.

	   NOTE: Does not exactly correspond to any low level API function. The implementation is
	   basen on openssl's "X509_digest()".

	    Net::SSLeay::X509_get_fingerprint($x509, $type);
	    # $x509 - value corresponding to openssl's X509 structure
	    # $type - (string) digest type, currently supported values:
	    #	      "md5"
	    #	      "sha1"
	    #	      "sha256"
	    #	      "ripemd160"
	    #
	    # returns: certificate digest - hexadecimal string (NOT binary data!)

       o   X509_get_issuer_name

	   Return an X509_NAME object representing the issuer of the certificate $cert.

	    my $rv = Net::SSLeay::X509_get_issuer_name($cert);
	    # $cert - value corresponding to openssl's X509 structure
	    #
	    # returns: value corresponding to openssl's X509_NAME structure (0 on failure)

       o   X509_get_notAfter

	   Return an object giving the time after which the certificate $cert is not valid.

	    my $rv = Net::SSLeay::X509_get_notAfter($cert);
	    # $cert - value corresponding to openssl's X509 structure
	    #
	    # returns: value corresponding to openssl's ASN1_TIME structure (0 on failure)

	   To get human readable/printable form the return value you can use:

	    my $time = Net::SSLeay::X509_get_notAfter($cert);
	    print "notAfter=", Net::SSLeay::P_ASN1_TIME_get_isotime($time), "\n";

       o   X509_get_notBefore

	   Return an object giving the time before which the certificate $cert is not valid

	    my $rv = Net::SSLeay::X509_get_notBefore($cert);
	    # $cert - value corresponding to openssl's X509 structure
	    #
	    # returns: value corresponding to openssl's ASN1_TIME structure (0 on failure)

	   To get human readable/printable form the return value you can use:

	    my $time = Net::SSLeay::X509_get_notBefore($cert);
	    print "notBefore=", Net::SSLeay::P_ASN1_TIME_get_isotime($time), "\n";

       o   X509_get_subjectAltNames

	   NOTE: Does not exactly correspond to any low level API function.

	   Returns the list of alternative subject names from X509 certificate $cert.

	    my @rv = Net::SSLeay::X509_get_subjectAltNames($cert);
	    # $cert - value corresponding to openssl's X509 structure
	    #
	    # returns: list containing pairs - name_type (integer), name_value (string)
	    #	       where name_type can be:
	    #	       0 - GEN_OTHERNAME
	    #	       1 - GEN_EMAIL
	    #	       2 - GEN_DNS
	    #	       3 - GEN_X400
	    #	       4 - GEN_DIRNAME
	    #	       5 - GEN_EDIPARTY
	    #	       6 - GEN_URI
	    #	       7 - GEN_IPADD
	    #	       8 - GEN_RID

       o   X509_get_subject_name

	   Returns the subject of the certificate $cert.

	    my $rv = Net::SSLeay::X509_get_subject_name($cert);
	    # $cert - value corresponding to openssl's X509 structure
	    #
	    # returns: value corresponding to openssl's X509_NAME structure (0 on failure)

       o   X509_gmtime_adj

	   Adjust th ASN1_TIME object to the timestamp (in GMT).

	    my $rv = Net::SSLeay::X509_gmtime_adj($s, $adj);
	    # $s - value corresponding to openssl's ASN1_TIME structure
	    # $adj - timestamp (seconds since 1.1.1970)
	    #
	    # returns: value corresponding to openssl's ASN1_TIME structure (0 on failure)

	   BEWARE: this function may fail for dates after 2038 as it is dependent on time_t size
	   on your system (32bit time_t does not work after 2038). Consider using
	   "P_ASN1_TIME_set_isotime" instead).

       o   X509_load_cert_crl_file

	   Takes PEM file and loads all X509 certificates and X509 CRLs from that file into
	   X509_LOOKUP structure.

	    my $rv = Net::SSLeay::X509_load_cert_crl_file($ctx, $file, $type);
	    # $ctx - value corresponding to openssl's X509_LOOKUP structure
	    # $file - (string) file name
	    # $type - (integer) type - use constants &Net::SSLeay::FILETYPE_PEM or &Net::SSLeay::FILETYPE_ASN1
	    #			       if not FILETYPE_PEM then behaves as Net::SSLeay::X509_load_cert_file()
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_load_cert_file

	   Loads/adds X509 certificate from $file to X509_LOOKUP structure

	    my $rv = Net::SSLeay::X509_load_cert_file($ctx, $file, $type);
	    # $ctx - value corresponding to openssl's X509_LOOKUP structure
	    # $file - (string) file name
	    # $type - (integer) type - use constants &Net::SSLeay::FILETYPE_PEM or &Net::SSLeay::FILETYPE_ASN1
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_load_crl_file

	   Loads/adds X509 CRL from $file to X509_LOOKUP structure

	    my $rv = Net::SSLeay::X509_load_crl_file($ctx, $file, $type);
	    # $ctx - value corresponding to openssl's X509_LOOKUP structure
	    # $file - (string) file name
	    # $type - (integer) type - use constants &Net::SSLeay::FILETYPE_PEM or &Net::SSLeay::FILETYPE_ASN1
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_policy_level_get0_node

	   ??? (more info needed)

	    my $rv = Net::SSLeay::X509_policy_level_get0_node($level, $i);
	    # $level - value corresponding to openssl's X509_POLICY_LEVEL structure
	    # $i - (integer) index/position
	    #
	    # returns: value corresponding to openssl's X509_POLICY_NODE structure (0 on failure)

       o   X509_policy_level_node_count

	   ??? (more info needed)

	    my $rv = Net::SSLeay::X509_policy_level_node_count($level);
	    # $level - value corresponding to openssl's X509_POLICY_LEVEL structure
	    #
	    # returns: (integer) node count

       o   X509_policy_node_get0_parent

	   ??? (more info needed)

	    my $rv = Net::SSLeay::X509_policy_node_get0_parent($node);
	    # $node - value corresponding to openssl's X509_POLICY_NODE structure
	    #
	    # returns: value corresponding to openssl's X509_POLICY_NODE structure (0 on failure)

       o   X509_policy_node_get0_policy

	   ??? (more info needed)

	    my $rv = Net::SSLeay::X509_policy_node_get0_policy($node);
	    # $node - value corresponding to openssl's X509_POLICY_NODE structure
	    #
	    # returns: value corresponding to openssl's ASN1_OBJECT structure (0 on failure)

       o   X509_policy_node_get0_qualifiers

	   ??? (more info needed)

	    my $rv = Net::SSLeay::X509_policy_node_get0_qualifiers($node);
	    # $node - value corresponding to openssl's X509_POLICY_NODE structure
	    #
	    # returns: value corresponding to openssl's STACK_OF(POLICYQUALINFO) structure (0 on failure)

       o   X509_policy_tree_free

	   ??? (more info needed)

	    Net::SSLeay::X509_policy_tree_free($tree);
	    # $tree - value corresponding to openssl's X509_POLICY_TREE structure
	    #
	    # returns: no return value

       o   X509_policy_tree_get0_level

	   ??? (more info needed)

	    my $rv = Net::SSLeay::X509_policy_tree_get0_level($tree, $i);
	    # $tree - value corresponding to openssl's X509_POLICY_TREE structure
	    # $i - (integer) level index
	    #
	    # returns: value corresponding to openssl's X509_POLICY_LEVEL structure (0 on failure)

       o   X509_policy_tree_get0_policies

	   ??? (more info needed)

	    my $rv = Net::SSLeay::X509_policy_tree_get0_policies($tree);
	    # $tree - value corresponding to openssl's X509_POLICY_TREE structure
	    #
	    # returns: value corresponding to openssl's X509_POLICY_NODE structure (0 on failure)

       o   X509_policy_tree_get0_user_policies

	   ??? (more info needed)

	    my $rv = Net::SSLeay::X509_policy_tree_get0_user_policies($tree);
	    # $tree - value corresponding to openssl's X509_POLICY_TREE structure
	    #
	    # returns: value corresponding to openssl's X509_POLICY_NODE structure (0 on failure)

       o   X509_policy_tree_level_count

	   ??? (more info needed)

	    my $rv = Net::SSLeay::X509_policy_tree_level_count($tree);
	    # $tree - value corresponding to openssl's X509_POLICY_TREE structure
	    #
	    # returns: (integer) count

       o   X509_verify_cert_error_string

	   Returns a human readable error string for verification error $n.

	    my $rv = Net::SSLeay::X509_verify_cert_error_string($n);
	    # $n - (long) numeric error code
	    #
	    # returns: error string

	   Check openssl doc <http://www.openssl.org/docs/crypto/X509_STORE_CTX_get_error.html>

       o   P_X509_add_extensions

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Adds one or more X509 extensions to X509 object $x.

	    my $rv = Net::SSLeay::P_X509_add_extensions($x, $ca_cert, $nid, $value);
	    # $x - value corresponding to openssl's X509 structure
	    # $ca_cert - value corresponding to openssl's X509 structure (issuer's cert - necessary for sertting NID_authority_key_identifier)
	    # $nid - NID identifying extension to be set
	    # $value - extension value
	    #
	    # returns: 1 on success, 0 on failure

	   You can set more extensions at once:

	    my $rv = Net::SSLeay::P_X509_add_extensions($x509, $ca_cert,
			   &Net::SSLeay::NID_key_usage => 'digitalSignature,keyEncipherment',
			   &Net::SSLeay::NID_subject_key_identifier => 'hash',
			   &Net::SSLeay::NID_authority_key_identifier => 'keyid',
			   &Net::SSLeay::NID_authority_key_identifier => 'issuer',
			   &Net::SSLeay::NID_basic_constraints => 'CA:FALSE',
			   &Net::SSLeay::NID_ext_key_usage => 'serverAuth,clientAuth',
			   &Net::SSLeay::NID_netscape_cert_type => 'server',
			   &Net::SSLeay::NID_subject_alt_name => 'DNS:s1.dom.com,DNS:s2.dom.com,DNS:s3.dom.com',
		     );

       o   P_X509_copy_extensions

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Copies X509 extensions from X509_REQ object to X509 object - handy when you need to
	   turn X509_REQ into X509 certificate.

	    Net::SSLeay::P_X509_copy_extensions($x509_req, $x509, $override);
	    # $x509_req - value corresponding to openssl's X509_REQ structure
	    # $x509 - value corresponding to openssl's X509 structure
	    # $override - (integer) flag indication whether to override already existing items in $x509 (default 1)
	    #
	    # returns: 1 on success, 0 on failure

       o   P_X509_get_crl_distribution_points

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before; requires at least
	   openssl-0.9.7

	   Get the list of CRL distribution points from X509 certificate.

	    my @cdp = Net::SSLeay::P_X509_get_crl_distribution_points($x509);
	    # $x509 - value corresponding to openssl's X509 structure
	    #
	    # returns: list of distribution points (usually URLs)

       o   P_X509_get_ext_key_usage

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before; requires at least
	   openssl-0.9.7

	   Gets the list of extended key usage of given X509 certificate $cert.

	    my @ext_usage = Net::SSLeay::P_X509_get_ext_key_usage($cert, $format);
	    # $cert - value corresponding to openssl's X509 structure
	    # $format - choose type of return values: 0=OIDs, 1=NIDs, 2=shortnames, 3=longnames
	    #
	    # returns: list of values

	   Examples:

	    my @extkeyusage_oid = Net::SSLeay::P_X509_get_ext_key_usage($x509,0);
	    # returns for example: ("1.3.6.1.5.5.7.3.1", "1.3.6.1.5.5.7.3.2")

	    my @extkeyusage_nid = Net::SSLeay::P_X509_get_ext_key_usage($x509,1);
	    # returns for example: (129, 130)

	    my @extkeyusage_sn	= Net::SSLeay::P_X509_get_ext_key_usage($x509,2);
	    # returns for example: ("serverAuth", "clientAuth")

	    my @extkeyusage_ln	= Net::SSLeay::P_X509_get_ext_key_usage($x509,3);
	    # returns for example: ("TLS Web Server Authentication",  "TLS Web Client Authentication")

       o   P_X509_get_key_usage

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Gets the list of key usage of given X509 certificate $cert.

	    my @keyusage = Net::SSLeay::P_X509_get_key_usage($cert);
	    # $cert - value corresponding to openssl's X509 structure
	    #
	    # returns: list of key usage values which can be none, one or more from the following list:
	    #	       "digitalSignature"
	    #	       "nonRepudiation"
	    #	       "keyEncipherment"
	    #	       "dataEncipherment"
	    #	       "keyAgreement"
	    #	       "keyCertSign"
	    #	       "cRLSign"
	    #	       "encipherOnly"
	    #	       "decipherOnly"

       o   P_X509_get_netscape_cert_type

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Gets the list of Netscape cert types of given X509 certificate $cert.

	    Net::SSLeay::P_X509_get_netscape_cert_type($cert);
	    # $cert - value corresponding to openssl's X509 structure
	    #
	    # returns: list of Netscape type values which can be none, one or more from the following list:
	    #	       "client"
	    #	       "server"
	    #	       "email"
	    #	       "objsign"
	    #	       "reserved"
	    #	       "sslCA"
	    #	       "emailCA"
	    #	       "objCA"

       o   P_X509_get_pubkey_alg

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Returns ASN1_OBJECT corresponding to X509 certificate public key algorithm.

	    my $rv = Net::SSLeay::P_X509_get_pubkey_alg($x);
	    # $x - value corresponding to openssl's X509 structure
	    #
	    # returns: value corresponding to openssl's ASN1_OBJECT structure (0 on failure)

	   To get textual representation use:

	    my $alg = Net::SSLeay::OBJ_obj2txt(Net::SSLeay::P_X509_get_pubkey_alg($x509));
	    # returns for example: "rsaEncryption"

       o   P_X509_get_signature_alg

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Returns ASN1_OBJECT corresponding to X509 signarite key algorithm.

	    my $rv = Net::SSLeay::P_X509_get_signature_alg($x);
	    # $x - value corresponding to openssl's X509 structure
	    #
	    # returns: value corresponding to openssl's ASN1_OBJECT structure (0 on failure)

	   To get textual representation use:

	    my $alg = Net::SSLeay::OBJ_obj2txt(Net::SSLeay::P_X509_get_signature_alg($x509))
	    # returns for example: "sha1WithRSAEncryption"

       Low level API: X509_REQ_* related functions

       o   X509_REQ_new

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Creates a new X509_REQ structure.

	    my $rv = Net::SSLeay::X509_REQ_new();
	    #
	    # returns: value corresponding to openssl's X509_REQ structure (0 on failure)

       o   X509_REQ_free

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Free an allocated X509_REQ structure.

	    Net::SSLeay::X509_REQ_free($x);
	    # $x - value corresponding to openssl's X509_REQ structure
	    #
	    # returns: no return value

       o   X509_REQ_add1_attr_by_NID

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Adds an attribute whose name is defined by a NID $nid. The field value to be added is
	   in $bytes.

	    my $rv = Net::SSLeay::X509_REQ_add1_attr_by_NID($req, $nid, $type, $bytes);
	    # $req - value corresponding to openssl's X509_REQ structure
	    # $nid - (integer) NID value
	    # $type - (integer) type of data in $bytes (see below)
	    # $bytes - data to be set
	    #
	    # returns: 1 on success, 0 on failure

	    # values for $type - use constants:
	    &Net::SSLeay::MBSTRING_UTF8     - $bytes contains utf8 encoded data
	    &Net::SSLeay::MBSTRING_ASC	    - $bytes contains ASCII data

       o   X509_REQ_digest

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Computes digest/fingerprint of X509_REQ $data using $type hash function.

	    my $digest_value = Net::SSLeay::X509_REQ_digest($data, $type);
	    # $data - value corresponding to openssl's X509_REQ structure
	    # $type - value corresponding to openssl's EVP_MD structure - e.g. got via EVP_get_digestbyname()
	    #
	    # returns: hash value (binary)

	    #to get printable (hex) value of digest use:
	    print unpack('H*', $digest_value);

       o   X509_REQ_get_attr_by_NID

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Retrieve the next index matching $nid after $lastpos ($lastpos should initially be set
	   to -1).

	    my $rv = Net::SSLeay::X509_REQ_get_attr_by_NID($req, $nid, $lastpos=-1);
	    # $req - value corresponding to openssl's X509_REQ structure
	    # $nid - (integer) NID value
	    # $lastpos - [optional] (integer) index where to start search (default -1)
	    #
	    # returns: index (-1 if there are no more entries)

	   Note: use "P_X509_REQ_get_attr" to get the actual attribute value - e.g.

	    my $index = Net::SSLeay::X509_REQ_get_attr_by_NID($req, $nid);
	    my @attr_values = Net::SSLeay::P_X509_REQ_get_attr($req, $index);

       o   X509_REQ_get_attr_by_OBJ

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Retrieve the next index matching $obj after $lastpos ($lastpos should initially be set
	   to -1).

	    my $rv = Net::SSLeay::X509_REQ_get_attr_by_OBJ($req, $obj, $lastpos=-1);
	    # $req - value corresponding to openssl's X509_REQ structure
	    # $obj - value corresponding to openssl's ASN1_OBJECT structure
	    # $lastpos - [optional] (integer) index where to start search (default -1)
	    #
	    # returns: index (-1 if there are no more entries)

	   Note: use "P_X509_REQ_get_attr" to get the actual attribute value - e.g.

	    my $index = Net::SSLeay::X509_REQ_get_attr_by_NID($req, $nid);
	    my @attr_values = Net::SSLeay::P_X509_REQ_get_attr($req, $index);

       o   X509_REQ_get_attr_count

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Returns the total number of attributes in $req.

	    my $rv = Net::SSLeay::X509_REQ_get_attr_count($req);
	    # $req - value corresponding to openssl's X509_REQ structure
	    #
	    # returns: (integer) items count

       o   X509_REQ_get_pubkey

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Returns public key corresponding to given X509_REQ object $x.

	    my $rv = Net::SSLeay::X509_REQ_get_pubkey($x);
	    # $x - value corresponding to openssl's X509_REQ structure
	    #
	    # returns: value corresponding to openssl's EVP_PKEY structure (0 on failure)

       o   X509_REQ_get_subject_name

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Returns X509_NAME object corresponding to subject name of given X509_REQ object $x.

	    my $rv = Net::SSLeay::X509_REQ_get_subject_name($x);
	    # $x - value corresponding to openssl's X509_REQ structure
	    #
	    # returns: value corresponding to openssl's X509_NAME structure (0 on failure)

       o   X509_REQ_get_version

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Returns 'version' value for given X509_REQ object $x.

	    my $rv = Net::SSLeay::X509_REQ_get_version($x);
	    # $x - value corresponding to openssl's X509_REQ structure
	    #
	    # returns: (integer) version e.g. 0 = "version 1"

       o   X509_REQ_set_pubkey

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Sets public key of given X509_REQ object $x to $pkey.

	    my $rv = Net::SSLeay::X509_REQ_set_pubkey($x, $pkey);
	    # $x - value corresponding to openssl's X509_REQ structure
	    # $pkey - value corresponding to openssl's EVP_PKEY structure
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_REQ_set_subject_name

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Sets subject name of given X509_REQ object $x to X509_NAME object $name.

	    my $rv = Net::SSLeay::X509_REQ_set_subject_name($x, $name);
	    # $x - value corresponding to openssl's X509_REQ structure
	    # $name - value corresponding to openssl's X509_NAME structure
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_REQ_set_version

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Sets 'version' of given X509_REQ object $x to $version.

	    my $rv = Net::SSLeay::X509_REQ_set_version($x, $version);
	    # $x - value corresponding to openssl's X509_REQ structure
	    # $version - (integer) e.g. 0 = "version 1"
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_REQ_sign

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Sign X509_REQ object $x with private key $pk (using digest algorithm $md).

	    my $rv = Net::SSLeay::X509_REQ_sign($x, $pk, $md);
	    # $x - value corresponding to openssl's X509_REQ structure
	    # $pk - value corresponding to openssl's EVP_PKEY structure (requestor's private key)
	    # $md - value corresponding to openssl's EVP_MD structure
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_REQ_verify

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Verifies X509_REQ object $x using public key $r (pubkey of requesting party).

	    my $rv = Net::SSLeay::X509_REQ_verify($x, $r);
	    # $x - value corresponding to openssl's X509_REQ structure
	    # $r - value corresponding to openssl's EVP_PKEY structure
	    #
	    # returns: 0 - verify failure, 1 - verify OK, <0 - error

       o   P_X509_REQ_add_extensions

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Adds one or more X509 extensions to X509_REQ object $x.

	    my $rv = Net::SSLeay::P_X509_REQ_add_extensions($x, $nid, $value);
	    # $x - value corresponding to openssl's X509_REQ structure
	    # $nid - NID identifying extension to be set
	    # $value - extension value
	    #
	    # returns: 1 on success, 0 on failure

	   You can set more extensions at once:

	    my $rv = Net::SSLeay::P_X509_REQ_add_extensions($x509_req,
		       &Net::SSLeay::NID_key_usage => 'digitalSignature,keyEncipherment',
		       &Net::SSLeay::NID_basic_constraints => 'CA:FALSE',
		       &Net::SSLeay::NID_ext_key_usage => 'serverAuth,clientAuth',
		       &Net::SSLeay::NID_netscape_cert_type => 'server',
		       &Net::SSLeay::NID_subject_alt_name => 'DNS:s1.com,DNS:s2.com',
		       &Net::SSLeay::NID_crl_distribution_points => 'URI:http://pki.com/crl1,URI:http://pki.com/crl2',
		     );

       o   P_X509_REQ_get_attr

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before; requires at least
	   openssl-0.9.7

	   Returns attribute value for X509_REQ's attribute at index $n.

	    Net::SSLeay::P_X509_REQ_get_attr($req, $n);
	    # $req - value corresponding to openssl's X509_REQ structure
	    # $n - (integer) attribute index
	    #
	    # returns: value corresponding to openssl's ASN1_STRING structure

       Low level API: X509_CRL_* related functions

       o   X509_CRL_new

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Creates a new X509_CRL structure.

	    my $rv = Net::SSLeay::X509_CRL_new();
	    #
	    # returns: value corresponding to openssl's X509_CRL structure (0 on failure)

       o   X509_CRL_free

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Free an allocated X509_CRL structure.

	    Net::SSLeay::X509_CRL_free($x);
	    # $x - value corresponding to openssl's X509_CRL structure
	    #
	    # returns: no return value

       o   X509_CRL_digest

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Computes digest/fingerprint of X509_CRL $data using $type hash function.

	    my $digest_value = Net::SSLeay::X509_CRL_digest($data, $type);
	    # $data - value corresponding to openssl's X509_CRL structure
	    # $type - value corresponding to openssl's EVP_MD structure - e.g. got via EVP_get_digestbyname()
	    #
	    # returns: hash value (binary)

	   Example:

	    my $x509_crl
	    my $md = Net::SSLeay::EVP_get_digestbyname("sha1");
	    my $digest_value = Net::SSLeay::X509_CRL_digest($x509_crl, $md);
	    #to get printable (hex) value of digest use:
	    print "digest=", unpack('H*', $digest_value), "\n";

       o   X509_CRL_get_ext

	   COMPATIBILITY: not available in Net-SSLeay-1.54 and before

	   Returns X509_EXTENSION from $x509 based on given position/index.

	    my $rv = Net::SSLeay::X509_CRL_get_ext($x509, $index);
	    # $x509 - value corresponding to openssl's X509_CRL structure
	    # $index - (integer) position/index of extension within $x509
	    #
	    # returns: value corresponding to openssl's X509_EXTENSION structure (0 on failure)

       o   X509_CRL_get_ext_by_NID

	   COMPATIBILITY: not available in Net-SSLeay-1.54 and before

	   Returns X509_EXTENSION from $x509 based on given NID.

	    my $rv = Net::SSLeay::X509_CRL_get_ext_by_NID($x509, $nid, $loc);
	    # $x509 - value corresponding to openssl's X509_CRL structure
	    # $nid - (integer) NID value
	    # $loc - (integer) position to start lookup at
	    #
	    # returns: position/index of extension, negative value on error
	    #	       call Net::SSLeay::X509_CRL_get_ext($x509, $rv) to get the actual extension

       o   X509_CRL_get_ext_count

	   COMPATIBILITY: not available in Net-SSLeay-1.54 and before

	   Returns the total number of extensions in X509_CRL object $x.

	    my $rv = Net::SSLeay::X509_CRL_get_ext_count($x);
	    # $x - value corresponding to openssl's X509_CRL structure
	    #
	    # returns: count of extensions

       o   X509_CRL_get_issuer

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Returns X509_NAME object corresponding to the issuer of X509_CRL $x.

	    my $rv = Net::SSLeay::X509_CRL_get_issuer($x);
	    # $x - value corresponding to openssl's X509_CRL structure
	    #
	    # returns: value corresponding to openssl's X509_NAME structure (0 on failure)

	   See other "X509_NAME_*" functions to get more info from X509_NAME structure.

       o   X509_CRL_get_lastUpdate

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Returns 'lastUpdate' date-time value of X509_CRL object $x.

	    my $rv = Net::SSLeay::X509_CRL_get_lastUpdate($x);
	    # $x - value corresponding to openssl's X509_CRL structure
	    #
	    # returns: value corresponding to openssl's ASN1_TIME structure (0 on failure)

       o   X509_CRL_get_nextUpdate

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Returns 'nextUpdate' date-time value of X509_CRL object $x.

	    my $rv = Net::SSLeay::X509_CRL_get_nextUpdate($x);
	    # $x - value corresponding to openssl's X509_CRL structure
	    #
	    # returns: value corresponding to openssl's ASN1_TIME structure (0 on failure)

       o   X509_CRL_get_version

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Returns 'version' value of given X509_CRL structure $x.

	    my $rv = Net::SSLeay::X509_CRL_get_version($x);
	    # $x - value corresponding to openssl's X509_CRL structure
	    #
	    # returns: (integer) version

       o   X509_CRL_set_issuer_name

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before; requires at least
	   openssl-0.9.7

	   Sets the issuer of X509_CRL object $x to X509_NAME object $name.

	    my $rv = Net::SSLeay::X509_CRL_set_issuer_name($x, $name);
	    # $x - value corresponding to openssl's X509_CRL structure
	    # $name - value corresponding to openssl's X509_NAME structure
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_CRL_set_lastUpdate

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before; requires at least
	   openssl-0.9.7

	   Sets 'lastUpdate' value of X509_CRL object $x to $tm.

	    my $rv = Net::SSLeay::X509_CRL_set_lastUpdate($x, $tm);
	    # $x - value corresponding to openssl's X509_CRL structure
	    # $tm - value corresponding to openssl's ASN1_TIME structure
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_CRL_set_nextUpdate

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before; requires at least
	   openssl-0.9.7

	   Sets 'nextUpdate' value of X509_CRL object $x to $tm.

	    my $rv = Net::SSLeay::X509_CRL_set_nextUpdate($x, $tm);
	    # $x - value corresponding to openssl's X509_CRL structure
	    # $tm - value corresponding to openssl's ASN1_TIME structure
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_CRL_set_version

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before; requires at least
	   openssl-0.9.7

	   Sets 'version' value of given X509_CRL structure $x to $version.

	    my $rv = Net::SSLeay::X509_CRL_set_version($x, $version);
	    # $x - value corresponding to openssl's X509_CRL structure
	    # $version - (integer) version number (1 = version 2 CRL)
	    #
	    # returns: 1 on success, 0 on failure

	   Note that if you want to use any X509_CRL extension you need to set "version 2 CRL" -
	   "Net::SSLeay::X509_CRL_set_version($x, 1)".

       o   X509_CRL_sign

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Sign X509_CRL object $x with private key $pkey (using digest algorithm $md).

	    my $rv = Net::SSLeay::X509_CRL_sign($x, $pkey, $md);
	    # $x - value corresponding to openssl's X509_CRL structure
	    # $pkey - value corresponding to openssl's EVP_PKEY structure
	    # $md - value corresponding to openssl's EVP_MD structure
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_CRL_sort

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before; requires at least
	   openssl-0.9.7

	   Sorts the data of X509_CRL object so it will be written in serial number order.

	    my $rv = Net::SSLeay::X509_CRL_sort($x);
	    # $x - value corresponding to openssl's X509_CRL structure
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_CRL_verify

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Verifies X509_CRL object $a using public key $r (pubkey of issuing CA).

	    my $rv = Net::SSLeay::X509_CRL_verify($a, $r);
	    # $a - value corresponding to openssl's X509_CRL structure
	    # $r - value corresponding to openssl's EVP_PKEY structure
	    #
	    # returns: 0 - verify failure, 1 - verify OK, <0 - error

       o   P_X509_CRL_add_revoked_serial_hex

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before; requires at least
	   openssl-0.9.7

	   Adds given serian number $serial_hex to X509_CRL object $crl.

	    Net::SSLeay::P_X509_CRL_add_revoked_serial_hex($crl, $serial_hex, $rev_time, $reason_code, $comp_time);
	    # $crl - value corresponding to openssl's X509_CRL structure
	    # $serial_hex - string (hexadecimal) representation of serial number
	    # $rev_time - (revocation time) value corresponding to openssl's ASN1_TIME structure
	    # $reason_code - [optional] (integer) reason code (see below) - default 0
	    # $comp_time - [optional] (compromise time) value corresponding to openssl's ASN1_TIME structure
	    #
	    # returns: no return value

	    reason codes:
	    0 - unspecified
	    1 - keyCompromise
	    2 - CACompromise
	    3 - affiliationChanged
	    4 - superseded
	    5 - cessationOfOperation
	    6 - certificateHold
	    7 - removeFromCRL

       o   P_X509_CRL_get_serial

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before; requires at least
	   openssl-0.9.7

	   Returns serial number of X509_CRL object.

	    my $rv = Net::SSLeay::P_X509_CRL_get_serial($crl);
	    # $crl - value corresponding to openssl's X509_CRL structure
	    #
	    # returns: value corresponding to openssl's ASN1_INTEGER structure (0 on failure)

       o   P_X509_CRL_set_serial

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before; requires at least
	   openssl-0.9.7

	   Sets serial number of X509_CRL object to $crl_number.

	    my $rv = Net::SSLeay::P_X509_CRL_set_serial($crl, $crl_number);
	    # $crl - value corresponding to openssl's X509_CRL structure
	    # $crl_number - value corresponding to openssl's ASN1_INTEGER structure
	    #
	    # returns: 1 on success, 0 on failure

       Low level API: X509_EXTENSION_* related functions

       o   X509_EXTENSION_get_critical

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Returns 'critical' flag of given X509_EXTENSION object $ex.

	    my $rv = Net::SSLeay::X509_EXTENSION_get_critical($ex);
	    # $ex - value corresponding to openssl's X509_EXTENSION structure
	    #
	    # returns: (integer) 1 - critical, 0 - noncritical

       o   X509_EXTENSION_get_data

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Returns value (raw data) of X509_EXTENSION object $ne.

	    my $rv = Net::SSLeay::X509_EXTENSION_get_data($ne);
	    # $ne - value corresponding to openssl's X509_EXTENSION structure
	    #
	    # returns: value corresponding to openssl's ASN1_OCTET_STRING structure (0 on failure)

	   Note: you can use "P_ASN1_STRING_get" to convert ASN1_OCTET_STRING into perl scalar
	   variable.

       o   X509_EXTENSION_get_object

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Returns OID (ASN1_OBJECT) of X509_EXTENSION object $ne.

	    my $rv = Net::SSLeay::X509_EXTENSION_get_object($ex);
	    # $ex - value corresponding to openssl's X509_EXTENSION structure
	    #
	    # returns: value corresponding to openssl's ASN1_OBJECT structure (0 on failure)

       o   X509V3_EXT_print

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Returns string representation of given X509_EXTENSION object $ext.

	    Net::SSLeay::X509V3_EXT_print($ext, $flags, $utf8_decode);
	    # $ext - value corresponding to openssl's X509_EXTENSION structure
	    # $flags - [optional] (integer) Currently the flag argument is unused and should be set to 0
	    # $utf8_decode - [optional] 0 or 1 whether the returned value should be utf8 decoded (default=0)
	    #
	    # returns: no return value

       o   X509V3_EXT_d2i

	   Parses an extension and returns its internal structure.

	    my $rv = Net::SSLeay::X509V3_EXT_d2i($ext);
	    # $ext - value corresponding to openssl's X509_EXTENSION structure
	    #
	    # returns: pointer ???

       Low level API: X509_NAME_* related functions

       o   X509_NAME_ENTRY_get_data

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Retrieves the field value of $ne in and ASN1_STRING structure.

	    my $rv = Net::SSLeay::X509_NAME_ENTRY_get_data($ne);
	    # $ne - value corresponding to openssl's X509_NAME_ENTRY structure
	    #
	    # returns: value corresponding to openssl's ASN1_STRING structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/crypto/X509_NAME_ENTRY_get_object.html>

       o   X509_NAME_ENTRY_get_object

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Retrieves the field name of $ne in and ASN1_OBJECT structure.

	    my $rv = Net::SSLeay::X509_NAME_ENTRY_get_object($ne);
	    # $ne - value corresponding to openssl's X509_NAME_ENTRY structure
	    #
	    # returns: value corresponding to openssl's ASN1_OBJECT structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/crypto/X509_NAME_ENTRY_get_object.html>

       o   X509_NAME_new

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before; requires at least
	   openssl-0.9.5

	   Creates a new X509_NAME structure.  Adds a field whose name is defined by a string
	   $field. The field value to be added is in $bytes.

	    my $rv = Net::SSLeay::X509_NAME_new();
	    #
	    # returns: value corresponding to openssl's X509_NAME structure (0 on failure)

       o   X509_NAME_hash

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before; requires at least
	   openssl-0.9.5

	   Sort of a checksum of issuer name $name.  The result is not a full hash (e.g. sha-1),
	   it is kind-of-a-hash truncated to the size of 'unsigned long' (32 bits).  The
	   resulting value might differ across different openssl versions for the same X509
	   certificate.

	    my $rv = Net::SSLeay::X509_NAME_hash($name);
	    # $name - value corresponding to openssl's X509_NAME structure
	    #
	    # returns: number representing checksum

       o   X509_NAME_add_entry_by_txt

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before; requires at least
	   openssl-0.9.5

	   Adds a field whose name is defined by a string $field. The field value to be added is
	   in $bytes.

	    my $rv = Net::SSLeay::X509_NAME_add_entry_by_txt($name, $field, $type, $bytes, $len, $loc, $set);
	    # $name - value corresponding to openssl's X509_NAME structure
	    # $field - (string) field definition (name) - e.g. "organizationName"
	    # $type - (integer) type of data in $bytes (see below)
	    # $bytes - data to be set
	    # $loc - [optional] (integer) index where the new entry is inserted: if it is -1 (default) it is appended
	    # $set - [optional] (integer) determines how the new type is added. If it is 0 (default) a new RDN is created
	    #
	    # returns: 1 on success, 0 on failure

	    # values for $type - use constants:
	    &Net::SSLeay::MBSTRING_UTF8     - $bytes contains utf8 encoded data
	    &Net::SSLeay::MBSTRING_ASC	    - $bytes contains ASCII data

	   Unicode note: when passing non-ascii (unicode) string in $bytes do not forget to set
	   "$flags = &Net::SSLeay::MBSTRING_UTF8" and encode the perl $string via "$bytes =
	   encode('utf-8', $string)".

	   Check openssl doc <http://www.openssl.org/docs/crypto/X509_NAME_add_entry_by_txt.html>

       o   X509_NAME_add_entry_by_NID

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before; requires at least
	   openssl-0.9.5

	   Adds a field whose name is defined by a NID $nid. The field value to be added is in
	   $bytes.

	    my $rv = Net::SSLeay::X509_NAME_add_entry_by_NID($name, $nid, $type, $bytes, $len, $loc, $set);
	    # $name - value corresponding to openssl's X509_NAME structure
	    # $nid - (integer) field definition - NID value
	    # $type - (integer) type of data in $bytes (see below)
	    # $bytes - data to be set
	    # $loc - [optional] (integer) index where the new entry is inserted: if it is -1 (default) it is appended
	    # $set - [optional] (integer) determines how the new type is added. If it is 0 (default) a new RDN is created
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc <http://www.openssl.org/docs/crypto/X509_NAME_add_entry_by_txt.html>

       o   X509_NAME_add_entry_by_OBJ

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before; requires at least
	   openssl-0.9.5

	   Adds a field whose name is defined by a object (OID) $obj . The field value to be
	   added is in $bytes.

	    my $rv = Net::SSLeay::X509_NAME_add_entry_by_OBJ($name, $obj, $type, $bytes, $len, $loc, $set);
	    # $name - value corresponding to openssl's X509_NAME structure
	    # $obj - field definition - value corresponding to openssl's ASN1_OBJECT structure
	    # $type - (integer) type of data in $bytes (see below)
	    # $bytes - data to be set
	    # $loc - [optional] (integer) index where the new entry is inserted: if it is -1 (default) it is appended
	    # $set - [optional] (integer) determines how the new type is added. If it is 0 (default) a new RDN is created
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc <http://www.openssl.org/docs/crypto/X509_NAME_add_entry_by_txt.html>

       o   X509_NAME_cmp

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Compares two X509_NAME obejcts.

	    my $rv = Net::SSLeay::X509_NAME_cmp($a, $b);
	    # $a - value corresponding to openssl's X509_NAME structure
	    # $b - value corresponding to openssl's X509_NAME structure
	    #
	    # returns: 0 if $a matches $b; non zero otherwise

       o   X509_NAME_digest

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Computes digest/fingerprint of X509_NAME $data using $type hash function.

	    my $digest_value = Net::SSLeay::X509_NAME_digest($data, $type);
	    # $data - value corresponding to openssl's X509_NAME structure
	    # $type - value corresponding to openssl's EVP_MD structure - e.g. got via EVP_get_digestbyname()
	    #
	    # returns: hash value (binary)

	    #to get printable (hex) value of digest use:
	    print unpack('H*', $digest_value);

       o   X509_NAME_entry_count

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Returns the total number of entries in $name.

	    my $rv = Net::SSLeay::X509_NAME_entry_count($name);
	    # $name - value corresponding to openssl's X509_NAME structure
	    #
	    # returns: (integer) entries count

	   Check openssl doc <http://www.openssl.org/docs/crypto/X509_NAME_get_index_by_NID.html>

       o   X509_NAME_get_entry

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Retrieves the X509_NAME_ENTRY from $name corresponding to index $loc. Acceptable
	   values for $loc run from 0 to "Net::SSLeay::X509_NAME_entry_count($name)- 1". The
	   value returned is an internal pointer which must not be freed.

	    my $rv = Net::SSLeay::X509_NAME_get_entry($name, $loc);
	    # $name - value corresponding to openssl's X509_NAME structure
	    # $loc - (integer) index of wanted entry
	    #
	    # returns: value corresponding to openssl's X509_NAME_ENTRY structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/crypto/X509_NAME_get_index_by_NID.html>

       o   X509_NAME_print_ex

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Returns a string with human readable version of $name.

	    Net::SSLeay::X509_NAME_print_ex($name, $flags, $utf8_decode);
	    # $name - value corresponding to openssl's X509_NAME structure
	    # $flags - [optional] conversion flags (default XN_FLAG_RFC2253) - see below
	    # $utf8_decode - [optional] 0 or 1 whether the returned value should be utf8 decoded (default=0)
	    #
	    # returns: string representation of $name

	    #available conversion flags - use constants:
	    &Net::SSLeay::XN_FLAG_COMPAT
	    &Net::SSLeay::XN_FLAG_DN_REV
	    &Net::SSLeay::XN_FLAG_DUMP_UNKNOWN_FIELDS
	    &Net::SSLeay::XN_FLAG_FN_ALIGN
	    &Net::SSLeay::XN_FLAG_FN_LN
	    &Net::SSLeay::XN_FLAG_FN_MASK
	    &Net::SSLeay::XN_FLAG_FN_NONE
	    &Net::SSLeay::XN_FLAG_FN_OID
	    &Net::SSLeay::XN_FLAG_FN_SN
	    &Net::SSLeay::XN_FLAG_MULTILINE
	    &Net::SSLeay::XN_FLAG_ONELINE
	    &Net::SSLeay::XN_FLAG_RFC2253
	    &Net::SSLeay::XN_FLAG_SEP_COMMA_PLUS
	    &Net::SSLeay::XN_FLAG_SEP_CPLUS_SPC
	    &Net::SSLeay::XN_FLAG_SEP_MASK
	    &Net::SSLeay::XN_FLAG_SEP_MULTILINE
	    &Net::SSLeay::XN_FLAG_SEP_SPLUS_SPC
	    &Net::SSLeay::XN_FLAG_SPC_EQ

	   Most likely you will be fine with default:

	    Net::SSLeay::X509_NAME_print_ex($name, &Net::SSLeay::XN_FLAG_RFC2253);

	   Or you might want RFC2253-like output without utf8 chars escaping:

	    use Net::SSLeay qw/XN_FLAG_RFC2253 ASN1_STRFLGS_ESC_MSB/;
	    my $flag_rfc22536_utf8 = (XN_FLAG_RFC2253) & (~ ASN1_STRFLGS_ESC_MSB);
	    my $result = Net::SSLeay::X509_NAME_print_ex($name, $flag_rfc22536_utf8, 1);

	   Check openssl doc <http://www.openssl.org/docs/crypto/X509_NAME_print_ex.html>

       o   X509_NAME_get_text_by_NID

	   Retrieves the text from the first entry in name which matches $nid, if no such entry
	   exists -1 is returned.

	   openssl note: this is a legacy function which has various limitations which makes it
	   of minimal use in practice. It can only find the first matching entry and will copy
	   the contents of the field verbatim: this can be highly confusing if the target is a
	   muticharacter string type like a BMPString or a UTF8String.

	    Net::SSLeay::X509_NAME_get_text_by_NID($name, $nid);
	    # $name - value corresponding to openssl's X509_NAME structure
	    # $nid - NID value (integer)
	    #
	    # returns: text value

	   Check openssl doc <http://www.openssl.org/docs/crypto/X509_NAME_get_index_by_NID.html>

       o   X509_NAME_oneline

	   Return an ASCII version of $name.

	    Net::SSLeay::X509_NAME_oneline($name);
	    # $name - value corresponding to openssl's X509_NAME structure
	    #
	    # returns: (string) ASCII version of $name

	   Check openssl doc <http://www.openssl.org/docs/crypto/X509_NAME_print_ex.html>

       o   sk_X509_NAME_free

	   Free an allocated STACK_OF(X509_NAME) structure.

	    Net::SSLeay::sk_X509_NAME_free($sk);
	    # $sk - value corresponding to openssl's STACK_OF(X509_NAME) structure
	    #
	    # returns: no return value

       o   sk_X509_NAME_num

	   Return number of items in STACK_OF(X509_NAME)

	    my $rv = Net::SSLeay::sk_X509_NAME_num($sk);
	    # $sk - value corresponding to openssl's STACK_OF(X509_NAME) structure
	    #
	    # returns: number of items

       o   sk_X509_NAME_value

	   Returns X509_NAME from position $index in STACK_OF(X509_NAME)

	    my $rv = Net::SSLeay::sk_X509_NAME_value($sk, $i);
	    # $sk - value corresponding to openssl's STACK_OF(X509_NAME) structure
	    # $i - (integer) index/position
	    #
	    # returns: value corresponding to openssl's X509_NAME structure (0 on failure)

       o   add_file_cert_subjects_to_stack

	   Add a file of certs to a stack. All certs in $file that are not already in the
	   $stackCAs will be added.

	    my $rv = Net::SSLeay::add_file_cert_subjects_to_stack($stackCAs, $file);
	    # $stackCAs - value corresponding to openssl's STACK_OF(X509_NAME) structure
	    # $file - (string) filename
	    #
	    # returns: 1 on success, 0 on failure

       o   add_dir_cert_subjects_to_stack

	   Add a directory of certs to a stack. All certs in $dir that are not already in the
	   $stackCAs will be added.

	    my $rv = Net::SSLeay::add_dir_cert_subjects_to_stack($stackCAs, $dir);
	    # $stackCAs - value corresponding to openssl's STACK_OF(X509_NAME) structure
	    # $dir - (string) the directory to append from. All files in this directory will be examined as potential certs. Any that are acceptable to SSL_add_dir_cert_subjects_to_stack() that are not already in the stack will be included.
	    #
	    # returns: 1 on success, 0 on failure

       Low level API: X509_STORE_* related functions

       o   X509_STORE_CTX_get_current_cert

	   Returns the certificate in ctx which caused the error or 0 if no certificate is
	   relevant.

	    my $rv = Net::SSLeay::X509_STORE_CTX_get_current_cert($x509_store_ctx);
	    # $x509_store_ctx - value corresponding to openssl's X509_STORE_CTX structure
	    #
	    # returns: value corresponding to openssl's X509 structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/crypto/X509_STORE_CTX_get_error.html>

       o   X509_STORE_CTX_get_error

	   Returns the error code of $ctx.

	    my $rv = Net::SSLeay::X509_STORE_CTX_get_error($x509_store_ctx);
	    # $x509_store_ctx - value corresponding to openssl's X509_STORE_CTX structure
	    #
	    # returns: (integer) error code

	   For more info about erro code values check function "get_verify_result".

	   Check openssl doc <http://www.openssl.org/docs/crypto/X509_STORE_CTX_get_error.html>

       o   X509_STORE_CTX_get_error_depth

	   Returns the depth of the error. This is a non-negative integer representing where in
	   the certificate chain the error occurred. If it is zero it occurred in the end entity
	   certificate, one if it is the certificate which signed the end entity certificate and
	   so on.

	    my $rv = Net::SSLeay::X509_STORE_CTX_get_error_depth($x509_store_ctx);
	    # $x509_store_ctx - value corresponding to openssl's X509_STORE_CTX structure
	    #
	    # returns: (integer) depth

	   Check openssl doc <http://www.openssl.org/docs/crypto/X509_STORE_CTX_get_error.html>

       o   X509_STORE_CTX_get_ex_data

	   Is used to retrieve the information for $idx from $x509_store_ctx.

	    my $rv = Net::SSLeay::X509_STORE_CTX_get_ex_data($x509_store_ctx, $idx);
	    # $x509_store_ctx - value corresponding to openssl's X509_STORE_CTX structure
	    # $idx - (integer) index for application specific data
	    #
	    # returns: pointer to ???

       o   X509_STORE_CTX_set_ex_data

	   Is used to store application data at arg for idx into $x509_store_ctx.

	    my $rv = Net::SSLeay::X509_STORE_CTX_set_ex_data($x509_store_ctx, $idx, $data);
	    # $x509_store_ctx - value corresponding to openssl's X509_STORE_CTX structure
	    # $idx - (integer) ???
	    # $data - (pointer) ???
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_STORE_CTX_set_cert

	   Sets the certificate to be vertified in $x509_store_ctx to $x.

	    Net::SSLeay::X509_STORE_CTX_set_cert($x509_store_ctx, $x);
	    # $x509_store_ctx - value corresponding to openssl's X509_STORE_CTX structure
	    # $x - value corresponding to openssl's X509 structure
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/crypto/X509_STORE_CTX_new.html>

       o   X509_STORE_CTX_set_error

	   Sets the error code of $ctx to $s. For example it might be used in a verification
	   callback to set an error based on additional checks.

	    Net::SSLeay::X509_STORE_CTX_set_error($x509_store_ctx, $s);
	    # $x509_store_ctx - value corresponding to openssl's X509_STORE_CTX structure
	    # $s - (integer) error id
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/crypto/X509_STORE_CTX_get_error.html>

       o   X509_STORE_add_cert

	   Adds X509 certificate $x into the X509_STORE $store.

	    my $rv = Net::SSLeay::X509_STORE_add_cert($store, $x);
	    # $store - value corresponding to openssl's X509_STORE structure
	    # $x - value corresponding to openssl's X509 structure
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_STORE_add_crl

	   Adds X509 CRL $x into the X509_STORE $store.

	    my $rv = Net::SSLeay::X509_STORE_add_crl($store, $x);
	    # $store - value corresponding to openssl's X509_STORE structure
	    # $x - value corresponding to openssl's X509_CRL structure
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_STORE_set1_param

	   ??? (more info needed)

	    my $rv = Net::SSLeay::X509_STORE_set1_param($store, $pm);
	    # $store - value corresponding to openssl's X509_STORE structure
	    # $pm - value corresponding to openssl's X509_VERIFY_PARAM structure
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_STORE_set_flags

	    Net::SSLeay::X509_STORE_set_flags($ctx, $flags);
	    # $ctx - value corresponding to openssl's X509_STORE structure
	    # $flags - (unsigned long) flags to be set (bitmask)
	    #
	    # returns: no return value

	    #to create $flags value use:
	    0x0001 - X509_V_FLAG_CB_ISSUER_CHECK - Send issuer+subject checks to verify_cb
	    0x0002 - X509_V_FLAG_USE_CHECK_TIME - Use check time instead of current time
	    0x0004 - X509_V_FLAG_CRL_CHECK - Lookup CRLs
	    0x0008 - X509_V_FLAG_CRL_CHECK_ALL - Lookup CRLs for whole chain
	    0x0010 - X509_V_FLAG_IGNORE_CRITICAL - Ignore unhandled critical extensions
	    0x0020 - X509_V_FLAG_X509_STRICT - Disable workarounds for broken certificates
	    0x0040 - X509_V_FLAG_ALLOW_PROXY_CERTS - Enable proxy certificate validation
	    0x0080 - X509_V_FLAG_POLICY_CHECK - Enable policy checking
	    0x0100 - X509_V_FLAG_EXPLICIT_POLICY - Policy variable require-explicit-policy
	    0x0200 - X509_V_FLAG_INHIBIT_ANY - Policy variable inhibit-any-policy
	    0x0400 - X509_V_FLAG_INHIBIT_MAP - Policy variable inhibit-policy-mapping
	    0x0800 - X509_V_FLAG_NOTIFY_POLICY - Notify callback that policy is OK
	    0x1000 - X509_V_FLAG_EXTENDED_CRL_SUPPORT - Extended CRL features such as indirect CRLs, alternate CRL signing keys
	    0x2000 - X509_V_FLAG_USE_DELTAS - Delta CRL support
	    0x4000 - X509_V_FLAG_CHECK_SS_SIGNATURE - Check selfsigned CA signature

	    #or use corresponding constants like
	    $flags = &Net::SSLeay::X509_V_FLAG_CB_ISSUER_CHECK;
	    ...
	    $flags = &Net::SSLeay::X509_V_FLAG_CHECK_SS_SIGNATURE;

       o   X509_STORE_set_purpose

	    Net::SSLeay::X509_STORE_set_purpose($ctx, $purpose);
	    # $ctx - value corresponding to openssl's X509_STORE structure
	    # $purpose - (integer) purpose identifier
	    #
	    # returns: no return value

	   For more details about $purpose identifier check "CTX_set_purpose".

       o   X509_STORE_set_trust

	    Net::SSLeay::X509_STORE_set_trust($ctx, $trust);
	    # $ctx - value corresponding to openssl's X509_STORE structure
	    # $trust - (integer) trust identifier
	    #
	    # returns: no return value

	   For more details about $trust identifier check "CTX_set_trust".

       Low level API: X509_VERIFY_PARAM_* related functions

       o   X509_VERIFY_PARAM_add0_policy

	   Enables policy checking (it is disabled by default) and adds $policy to the acceptable
	   policy set.

	    my $rv = Net::SSLeay::X509_VERIFY_PARAM_add0_policy($param, $policy);
	    # $param - value corresponding to openssl's X509_VERIFY_PARAM structure
	    # $policy - value corresponding to openssl's ASN1_OBJECT structure
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_VERIFY_PARAM_set_flags.html>

       o   X509_VERIFY_PARAM_add0_table

	   ??? (more info needed)

	    my $rv = Net::SSLeay::X509_VERIFY_PARAM_add0_table($param);
	    # $param - value corresponding to openssl's X509_VERIFY_PARAM structure
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_VERIFY_PARAM_clear_flags

	   Clears the flags $flags in param.

	    my $rv = Net::SSLeay::X509_VERIFY_PARAM_clear_flags($param, $flags);
	    # $param - value corresponding to openssl's X509_VERIFY_PARAM structure
	    # $flags - (unsigned long) flags to be set (bitmask)
	    #
	    # returns: 1 on success, 0 on failure

	   For more details about $flags bitmask see "X509_STORE_set_flags".

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_VERIFY_PARAM_set_flags.html>

       o   X509_VERIFY_PARAM_free

	   Frees up the X509_VERIFY_PARAM structure.

	    Net::SSLeay::X509_VERIFY_PARAM_free($param);
	    # $param - value corresponding to openssl's X509_VERIFY_PARAM structure
	    #
	    # returns: no return value

       o   X509_VERIFY_PARAM_get_depth

	   Returns the current verification depth.

	    my $rv = Net::SSLeay::X509_VERIFY_PARAM_get_depth($param);
	    # $param - value corresponding to openssl's X509_VERIFY_PARAM structure
	    #
	    # returns: (ineger) depth

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_VERIFY_PARAM_set_flags.html>

       o   X509_VERIFY_PARAM_get_flags

	   Returns the current verification flags.

	    my $rv = Net::SSLeay::X509_VERIFY_PARAM_get_flags($param);
	    # $param - value corresponding to openssl's X509_VERIFY_PARAM structure
	    #
	    # returns: (unsigned long) flags to be set (bitmask)

	   For more details about returned flags bitmask see "X509_STORE_set_flags".

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_VERIFY_PARAM_set_flags.html>

       o   X509_VERIFY_PARAM_set_flags

	    my $rv = Net::SSLeay::X509_VERIFY_PARAM_set_flags($param, $flags);
	    # $param - value corresponding to openssl's X509_VERIFY_PARAM structure
	    # $flags - (unsigned long) flags to be set (bitmask)
	    #
	    # returns: 1 on success, 0 on failure

	   For more details about $flags bitmask see "X509_STORE_set_flags".

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_VERIFY_PARAM_set_flags.html>

       o   X509_VERIFY_PARAM_inherit

	   ??? (more info needed)

	    my $rv = Net::SSLeay::X509_VERIFY_PARAM_inherit($to, $from);
	    # $to - value corresponding to openssl's X509_VERIFY_PARAM structure
	    # $from - value corresponding to openssl's X509_VERIFY_PARAM structure
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_VERIFY_PARAM_lookup

	   Finds X509_VERIFY_PARAM by name.

	    my $rv = Net::SSLeay::X509_VERIFY_PARAM_lookup($name);
	    # $name - (string) name we want to find
	    #
	    # returns: value corresponding to openssl's X509_VERIFY_PARAM structure (0 on failure)

       o   X509_VERIFY_PARAM_new

	   Creates a new X509_VERIFY_PARAM structure.

	    my $rv = Net::SSLeay::X509_VERIFY_PARAM_new();
	    #
	    # returns: value corresponding to openssl's X509_VERIFY_PARAM structure (0 on failure)

       o   X509_VERIFY_PARAM_set1

	   Sets the name of X509_VERIFY_PARAM structure $to to the same value as the name of
	   X509_VERIFY_PARAM structure $from.

	    my $rv = Net::SSLeay::X509_VERIFY_PARAM_set1($to, $from);
	    # $to - value corresponding to openssl's X509_VERIFY_PARAM structure
	    # $from - value corresponding to openssl's X509_VERIFY_PARAM structure
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_VERIFY_PARAM_set1_name

	   Sets the name of X509_VERIFY_PARAM structure $param to $name.

	    my $rv = Net::SSLeay::X509_VERIFY_PARAM_set1_name($param, $name);
	    # $param - value corresponding to openssl's X509_VERIFY_PARAM structure
	    # $name - (string) name to be set
	    #
	    # returns: 1 on success, 0 on failure

       o   X509_VERIFY_PARAM_set1_policies

	   Enables policy checking (it is disabled by default) and sets the acceptable policy set
	   to policies.  Any existing policy set is cleared. The policies parameter can be 0 to
	   clear an existing policy set.

	    my $rv = Net::SSLeay::X509_VERIFY_PARAM_set1_policies($param, $policies);
	    # $param - value corresponding to openssl's X509_VERIFY_PARAM structure
	    # $policies - value corresponding to openssl's STACK_OF(ASN1_OBJECT) structure
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_VERIFY_PARAM_set_flags.html>

       o   X509_VERIFY_PARAM_set_depth

	   Sets the maximum verification depth to depth. That is the maximum number of untrusted
	   CA certificates that can appear in a chain.

	    Net::SSLeay::X509_VERIFY_PARAM_set_depth($param, $depth);
	    # $param - value corresponding to openssl's X509_VERIFY_PARAM structure
	    # $depth - (integer) depth to be set
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_VERIFY_PARAM_set_flags.html>

       o   X509_VERIFY_PARAM_set_purpose

	   Sets the verification purpose in $param to $purpose. This determines the acceptable
	   purpose of the certificate chain, for example SSL client or SSL server.

	    my $rv = Net::SSLeay::X509_VERIFY_PARAM_set_purpose($param, $purpose);
	    # $param - value corresponding to openssl's X509_VERIFY_PARAM structure
	    # $purpose - (integer) purpose identifier
	    #
	    # returns: 1 on success, 0 on failure

	   For more details about $purpose identifier check "CTX_set_purpose".

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_VERIFY_PARAM_set_flags.html>

       o   X509_VERIFY_PARAM_set_time

	   Sets the verification time in $param to $t. Normally the current time is used.

	    Net::SSLeay::X509_VERIFY_PARAM_set_time($param, $t);
	    # $param - value corresponding to openssl's X509_VERIFY_PARAM structure
	    # $t - (time_t) time in seconds since 1.1.1970
	    #
	    # returns: no return value

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_VERIFY_PARAM_set_flags.html>

       o   X509_VERIFY_PARAM_set_trust

	   Sets the trust setting in $param to $trust.

	    my $rv = Net::SSLeay::X509_VERIFY_PARAM_set_trust($param, $trust);
	    # $param - value corresponding to openssl's X509_VERIFY_PARAM structure
	    # $trust - (integer) trust identifier
	    #
	    # returns: 1 on success, 0 on failure

	   For more details about $trust identifier check "CTX_set_trust".

	   Check openssl doc
	   <http://www.openssl.org/docs/crypto/X509_VERIFY_PARAM_set_flags.html>

       o   X509_VERIFY_PARAM_table_cleanup

	   ??? (more info needed)

	    Net::SSLeay::X509_VERIFY_PARAM_table_cleanup();
	    #
	    # returns: no return value

       Low level API: Cipher (EVP_CIPHER_*) related functions

       o   EVP_get_cipherbyname

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before

	   Returns an EVP_CIPHER structure when passed a cipher name.

	    my $rv = Net::SSLeay::EVP_get_cipherbyname($name);
	    # $name - (string) cipher name e.g. 'aes-128-cbc', 'camellia-256-ecb', 'des-ede', ...
	    #
	    # returns: value corresponding to openssl's EVP_CIPHER structure

	   Check openssl doc <http://www.openssl.org/docs/crypto/EVP_EncryptInit.html>

       Low level API: Digest (EVP_MD_*) related functions

       o   OpenSSL_add_all_digests

	   COMPATIBILITY: not available in Net-SSLeay-1.42 and before

	    Net::SSLeay::OpenSSL_add_all_digests();
	    # no args, no return value

	   http://www.openssl.org/docs/crypto/OpenSSL_add_all_algorithms.html

       o   P_EVP_MD_list_all

	   COMPATIBILITY: not available in Net-SSLeay-1.42 and before; requires at least
	   openssl-1.0.0

	   NOTE: Does not exactly correspond to any low level API function

	    my $rv = Net::SSLeay::P_EVP_MD_list_all();
	    #
	    # returns: arrayref - list of available digest names

	   The returned digest names correspond to values expected by "EVP_get_digestbyname".

	   Note that some of the digets are available by default and some only after calling
	   "OpenSSL_add_all_digests".

       o   EVP_get_digestbyname

	   COMPATIBILITY: not available in Net-SSLeay-1.42 and before

	    my $rv = Net::SSLeay::EVP_get_digestbyname($name);
	    # $name - string with digest name
	    #
	    # returns: value corresponding to openssl's EVP_MD structure

	   The $name param can be:

	    md2
	    md4
	    md5
	    mdc2
	    ripemd160
	    sha
	    sha1
	    sha224
	    sha256
	    sha512
	    whirlpool

	   Or better check the supported digests by calling "P_EVP_MD_list_all".

       o   EVP_MD_type

	   COMPATIBILITY: not available in Net-SSLeay-1.42 and before

	    my $rv = Net::SSLeay::EVP_MD_type($md);
	    # $md - value corresponding to openssl's EVP_MD structure
	    #
	    # returns: the NID (integer) of the OBJECT IDENTIFIER representing the given message digest

       o   EVP_MD_size

	   COMPATIBILITY: not available in Net-SSLeay-1.42 and before

	    my $rv = Net::SSLeay::EVP_MD_size($md);
	    # $md - value corresponding to openssl's EVP_MD structure
	    #
	    # returns: the size of the message digest in bytes (e.g. 20 for SHA1)

       o   EVP_MD_CTX_md

	   COMPATIBILITY: not available in Net-SSLeay-1.42 and before; requires at least
	   openssl-0.9.7

	    Net::SSLeay::EVP_MD_CTX_md($ctx);
	    # $ctx - value corresponding to openssl's EVP_MD_CTX structure
	    #
	    # returns: value corresponding to openssl's EVP_MD structure

       o   EVP_MD_CTX_create

	   COMPATIBILITY: not available in Net-SSLeay-1.42 and before; requires at least
	   openssl-0.9.7

	   Allocates, initializes and returns a digest context.

	    my $rv = Net::SSLeay::EVP_MD_CTX_create();
	    #
	    # returns: value corresponding to openssl's EVP_MD_CTX structure

	   The complete idea behind EVP_MD_CTX looks like this example:

	     Net::SSLeay::OpenSSL_add_all_digests();

	     my $md = Net::SSLeay::EVP_get_digestbyname("sha1");
	     my $ctx = Net::SSLeay::EVP_MD_CTX_create();
	     Net::SSLeay::EVP_DigestInit($ctx, $md);

	     while(my $chunk = get_piece_of_data()) {
	       Net::SSLeay::EVP_DigestUpdate($ctx,$chunk);
	     }

	     my $result = Net::SSLeay::EVP_DigestFinal($ctx);
	     Net::SSLeay::EVP_MD_CTX_destroy($ctx);

	     print "digest=", unpack('H*', $result), "\n"; #print hex value

       o   EVP_DigestInit_ex

	   COMPATIBILITY: not available in Net-SSLeay-1.42 and before; requires at least
	   openssl-0.9.7

	   Sets up digest context $ctx to use a digest $type from ENGINE $impl, $ctx must be
	   initialized before calling this function, type will typically be supplied by a
	   function such as "EVP_get_digestbyname". If $impl is 0 then the default implementation
	   of digest $type is used.

	    my $rv = Net::SSLeay::EVP_DigestInit_ex($ctx, $type, $impl);
	    # $ctx  - value corresponding to openssl's EVP_MD_CTX structure
	    # $type - value corresponding to openssl's EVP_MD structure
	    # $impl - value corresponding to openssl's ENGINE structure
	    #
	    # returns: 1 for success and 0 for failure

       o   EVP_DigestInit

	   COMPATIBILITY: not available in Net-SSLeay-1.42 and before; requires at least
	   openssl-0.9.7

	   Behaves in the same way as "EVP_DigestInit_ex" except the passed context $ctx does not
	   have to be initialized, and it always uses the default digest implementation.

	    my $rv = Net::SSLeay::EVP_DigestInit($ctx, $type);
	    # $ctx - value corresponding to openssl's EVP_MD_CTX structure
	    # $type - value corresponding to openssl's EVP_MD structure
	    #
	    # returns: 1 for success and 0 for failure

       o   EVP_MD_CTX_destroy

	   COMPATIBILITY: not available in Net-SSLeay-1.42 and before; requires at least
	   openssl-0.9.7

	   Cleans up digest context $ctx and frees up the space allocated to it, it should be
	   called only on a context created using "EVP_MD_CTX_create".

	    Net::SSLeay::EVP_MD_CTX_destroy($ctx);
	    # $ctx - value corresponding to openssl's EVP_MD_CTX structure
	    #
	    # returns: no return value

       o   EVP_DigestUpdate

	   COMPATIBILITY: not available in Net-SSLeay-1.42 and before; requires at least
	   openssl-0.9.7

	    my $rv = Net::SSLeay::EVP_DigestUpdate($ctx, $data);
	    # $ctx  - value corresponding to openssl's EVP_MD_CTX structure
	    # $data - data to be hashed
	    #
	    # returns: 1 for success and 0 for failure

       o   EVP_DigestFinal_ex

	   COMPATIBILITY: not available in Net-SSLeay-1.42 and before; requires at least
	   openssl-0.9.7

	   Retrieves the digest value from $ctx. After calling "EVP_DigestFinal_ex" no additional
	   calls to "EVP_DigestUpdate" can be made, but "EVP_DigestInit_ex" can be called to
	   initialize a new digest operation.

	    my $digest_value = Net::SSLeay::EVP_DigestFinal_ex($ctx);
	    # $ctx - value corresponding to openssl's EVP_MD_CTX structure
	    #
	    # returns: hash value (binary)

	    #to get printable (hex) value of digest use:
	    print unpack('H*', $digest_value);

       o   EVP_DigestFinal

	   COMPATIBILITY: not available in Net-SSLeay-1.42 and before; requires at least
	   openssl-0.9.7

	   Similar to "EVP_DigestFinal_ex" except the digest context ctx is automatically cleaned
	   up.

	    my $rv = Net::SSLeay::EVP_DigestFinal($ctx);
	    # $ctx - value corresponding to openssl's EVP_MD_CTX structure
	    #
	    # returns: hash value (binary)

	    #to get printable (hex) value of digest use:
	    print unpack('H*', $digest_value);

       o   MD2

	   COMPATIBILITY: no supported by default in openssl-1.0.0

	   Computes MD2 from given $data (all data needs to be loaded into memory)

	    my $digest = Net::SSLeay::MD2($data);
	    print "digest(hexadecimal)=", unpack('H*', $digest);

       o   MD4

	   Computes MD4 from given $data (all data needs to be loaded into memory)

	    my $digest = Net::SSLeay::MD4($data);
	    print "digest(hexadecimal)=", unpack('H*', $digest);

       o   MD5

	   Computes MD5 from given $data (all data needs to be loaded into memory)

	    my $digest = Net::SSLeay::MD5($data);
	    print "digest(hexadecimal)=", unpack('H*', $digest);

       o   RIPEMD160

	   Computes RIPEMD160 from given $data (all data needs to be loaded into memory)

	    my $digest = Net::SSLeay::RIPEMD160($data);
	    print "digest(hexadecimal)=", unpack('H*', $digest);

       o   SHA1

	   COMPATIBILITY: not available in Net-SSLeay-1.42 and before

	   Computes SHA1 from given $data (all data needs to be loaded into memory)

	    my $digest = Net::SSLeay::SHA1($data);
	    print "digest(hexadecimal)=", unpack('H*', $digest);

       o   SHA256

	   COMPATIBILITY: not available in Net-SSLeay-1.42 and before; requires at least
	   openssl-0.9.8

	   Computes SHA256 from given $data (all data needs to be loaded into memory)

	    my $digest = Net::SSLeay::SHA256($data);
	    print "digest(hexadecimal)=", unpack('H*', $digest);

       o   SHA512

	   COMPATIBILITY: not available in Net-SSLeay-1.42 and before; requires at least
	   openssl-0.9.8

	   Computes SHA512 from given $data (all data needs to be loaded into memory)

	    my $digest = Net::SSLeay::SHA512($data);
	    print "digest(hexadecimal)=", unpack('H*', $digest);

       o   EVP_Digest

	   COMPATIBILITY: not available in Net-SSLeay-1.42 and before; requires at least
	   openssl-0.9.7

	   Computes "any" digest from given $data (all data needs to be loaded into memory)

	    my $md = Net::SSLeay::EVP_get_digestbyname("sha1"); #or any other algorithm
	    my $digest = Net::SSLeay::EVP_Digest($data, $md);
	    print "digest(hexadecimal)=", unpack('H*', $digest);

       o   EVP_sha1

	   COMPATIBILITY: not available in Net-SSLeay-1.42 and before

	    my $md = Net::SSLeay::EVP_sha1();
	    #
	    # returns: value corresponding to openssl's EVP_MD structure

       o   EVP_sha256

	   COMPATIBILITY: requires at least openssl-0.9.8

	    my $md = Net::SSLeay::EVP_sha256();
	    #
	    # returns: value corresponding to openssl's EVP_MD structure

       o   EVP_sha512

	   COMPATIBILITY: not available in Net-SSLeay-1.42 and before; requires at least
	   openssl-0.9.8

	    my $md = Net::SSLeay::EVP_sha512();
	    #
	    # returns: value corresponding to openssl's EVP_MD structure

       o   EVP_add_digest

	    my $rv = Net::SSLeay::EVP_add_digest($digest);
	    # $digest - value corresponding to openssl's EVP_MD structure
	    #
	    # returns: 1 on success, 0 otherwise

       Low level API: CIPHER_* related functions

       o   CIPHER_get_name

	   COMPATIBILITY: not available in Net-SSLeay-1.42 and before

	   Returns name of the cipher used.

	    my $rv = Net::SSLeay::CIPHER_description($cipher);
	    # $cipher - value corresponding to openssl's SSL_CIPHER structure
	    #
	    # returns: (string) cipher name e.g. 'DHE-RSA-AES256-SHA'

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CIPHER_get_name.html>

	   Example:

	    my $ssl_cipher = Net::SSLeay::get_current_cipher($ssl);
	    my $cipher_name = Net::SSLeay::CIPHER_get_name($ssl_cipher);

       o   CIPHER_description

	   Returns a textual description of the cipher used.

	   ??? (does this function really work?)

	    my $rv = Net::SSLeay::CIPHER_description($cipher, $buf, $size);
	    # $cipher - value corresponding to openssl's SSL_CIPHER structure
	    # $bufer - (string/buffer) ???
	    # $size - (integer) ???
	    #
	    # returns: (string) cipher description e.g. 'DHE-RSA-AES256-SHA SSLv3 Kx=DH Au=RSA Enc=AES(256) Mac=SHA1'

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CIPHER_get_name.html>

       o   CIPHER_get_bits

	   Returns the number of secret bits used for cipher.

	    my $rv = Net::SSLeay::CIPHER_get_bits($c);
	    # $c - value corresponding to openssl's SSL_CIPHER structure
	    #
	    # returns: (integert) number of secret bits, 0 on error

	   Check openssl doc <http://www.openssl.org/docs/ssl/SSL_CIPHER_get_name.html>

       Low level API: RSA_* related functions

       o   RSA_generate_key

	   Generates a key pair and returns it in a newly allocated RSA structure.  The pseudo-
	   random number generator must be seeded prior to calling RSA_generate_key.

	    my $rv = Net::SSLeay::RSA_generate_key($bits, $e, $perl_cb, $perl_cb_arg);
	    # $bits - (integer) modulus size in bits e.g. 512, 1024, 2048
	    # $e - (integer) public exponent, an odd number, typically 3, 17 or 65537
	    # $perl_cb - [optional] reference to perl callback function
	    # $perl_cb_arg - [optional] data that will be passed to callback function when invoked
	    #
	    # returns: value corresponding to openssl's RSA structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/crypto/RSA_generate_key.html>

       o   RSA_free

	   Frees the RSA structure and its components. The key is erased before the memory is
	   returned to the system.

	    Net::SSLeay::RSA_free($r);
	    # $r - value corresponding to openssl's RSA structure
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/crypto/RSA_new.html>

       Low level API: BIO_* related functions

       o   BIO_eof

	   Returns 1 if the BIO has read EOF, the precise meaning of 'EOF' varies according to
	   the BIO type.

	    my $rv = Net::SSLeay::BIO_eof($s);
	    # $s - value corresponding to openssl's BIO structure
	    #
	    # returns: 1 if EOF has been reached 0 otherwise

	   Check openssl doc <http://www.openssl.org/docs/crypto/BIO_ctrl.html>

       o   BIO_f_ssl

	   Returns the SSL BIO method. This is a filter BIO which is a wrapper round the OpenSSL
	   SSL routines adding a BIO 'flavour' to SSL I/O.

	    my $rv = Net::SSLeay::BIO_f_ssl();
	    #
	    # returns: value corresponding to openssl's BIO_METHOD structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/crypto/BIO_f_ssl.html>

       o   BIO_free

	   Frees up a single BIO.

	    my $rv = Net::SSLeay::BIO_free($bio;);
	    # $bio; - value corresponding to openssl's BIO structure
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc <http://www.openssl.org/docs/crypto/BIO_new.html>

       o   BIO_new

	   Returns a new BIO using method $type

	    my $rv = Net::SSLeay::BIO_new($type);
	    # $type - value corresponding to openssl's BIO_METHOD structure
	    #
	    # returns: value corresponding to openssl's BIO structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/crypto/BIO_new.html>

       o   BIO_new_buffer_ssl_connect

	   Creates a new BIO chain consisting of a buffering BIO, an SSL BIO (using ctx) and a
	   connect BIO.

	    my $rv = Net::SSLeay::BIO_new_buffer_ssl_connect($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: value corresponding to openssl's BIO structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/crypto/BIO_f_ssl.html>

       o   BIO_new_file

	   Creates a new file BIO with mode mode the meaning of mode is the same as the stdio
	   function fopen(). The BIO_CLOSE flag is set on the returned BIO.

	    my $rv = Net::SSLeay::BIO_new_file($filename, $mode);
	    # $filename - (string) filename
	    # $mode - (string) opening mode (as mode by stdio function fopen)
	    #
	    # returns: value corresponding to openssl's BIO structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/crypto/BIO_s_file.html>

       o   BIO_new_ssl

	   Allocates an SSL BIO using SSL_CTX ctx and using client mode if client is non zero.

	    my $rv = Net::SSLeay::BIO_new_ssl($ctx, $client);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $client - (integer) 0 or 1 - indicates ssl client mode
	    #
	    # returns: value corresponding to openssl's BIO structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/crypto/BIO_f_ssl.html>

       o   BIO_new_ssl_connect

	   Creates a new BIO chain consisting of an SSL BIO (using ctx) followed by a connect
	   BIO.

	    my $rv = Net::SSLeay::BIO_new_ssl_connect($ctx);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    #
	    # returns: value corresponding to openssl's BIO structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/crypto/BIO_f_ssl.html>

       o   BIO_pending

	   Return the number of pending characters in the BIOs read buffers.

	    my $rv = Net::SSLeay::BIO_pending($s);
	    # $s - value corresponding to openssl's BIO structure
	    #
	    # returns: the amount of pending data

	   Check openssl doc <http://www.openssl.org/docs/crypto/BIO_ctrl.html>

       o   BIO_wpending

	   Return the number of pending characters in the BIOs write buffers.

	    my $rv = Net::SSLeay::BIO_wpending($s);
	    # $s - value corresponding to openssl's BIO structure
	    #
	    # returns: the amount of pending data

	   Check openssl doc <http://www.openssl.org/docs/crypto/BIO_ctrl.html>

       o   BIO_read

	   Read the underlying descriptor.

	    Net::SSLeay::BIO_read($s, $max);
	    # $s - value corresponding to openssl's BIO structure
	    # $max - [optional] max. bytes to read (if not specified, the value 32768 is used)
	    #
	    # returns: data

	   Check openssl doc <http://www.openssl.org/docs/crypto/BIO_read.html>

       o   BIO_write

	   Attempts to write data from $buffer to BIO $b.

	    my $rv = Net::SSLeay::BIO_write($b, $buffer);
	    # $b - value corresponding to openssl's BIO structure
	    # $buffer - data
	    #
	    # returns: amount of data successfully written
	    #	       or that no data was successfully read or written if the result is 0 or -1
	    #	       or -2 when the operation is not implemented in the specific BIO type

	   Check openssl doc <http://www.openssl.org/docs/crypto/BIO_read.html>

       o   BIO_s_mem

	   Return the memory BIO method function.

	    my $rv = Net::SSLeay::BIO_s_mem();
	    #
	    # returns: value corresponding to openssl's BIO_METHOD structure (0 on failure)

	   Check openssl doc <http://www.openssl.org/docs/crypto/BIO_s_mem.html>

       o   BIO_ssl_copy_session_id

	   Copies an SSL session id between BIO chains from and to. It does this by locating the
	   SSL BIOs in each chain and calling SSL_copy_session_id() on the internal SSL pointer.

	    my $rv = Net::SSLeay::BIO_ssl_copy_session_id($to, $from);
	    # $to - value corresponding to openssl's BIO structure
	    # $from - value corresponding to openssl's BIO structure
	    #
	    # returns: 1 on success, 0 on failure

	   Check openssl doc <http://www.openssl.org/docs/crypto/BIO_f_ssl.html>

       o   BIO_ssl_shutdown

	   Closes down an SSL connection on BIO chain bio. It does this by locating the SSL BIO
	   in the chain and calling SSL_shutdown() on its internal SSL pointer.

	    Net::SSLeay::BIO_ssl_shutdown($ssl_bio);
	    # $ssl_bio - value corresponding to openssl's BIO structure
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/crypto/BIO_f_ssl.html>

       Low level API: Server side Server Name Indication (SNI) support

       o   set_tlsext_host_name

	   TBA

       o   get_servername

	   TBA

       o   get_servername_type

	   TBA

       o   CTX_set_tlsext_servername_callback

	   COMPATIBILITY: requires at least OpenSSL 0.9.8f

	   This function is used in a server to support Server side Server Name Indication (SNI).

	    Net::SSLeay::CTX_set_tlsext_servername_callback($ctx, $code)
	    # $ctx - SSL context
	    # $code - reference to a subroutine that will be called when a new connection is being initiated
	    #
	    # returns: no return value
	   On the client side:
	   use set_tlsext_host_name($ssl, $servername) before initiating the SSL connection.

	   On the server side: Set up an additional SSL_CTX() for each different certificate;

	   Add a servername callback to each SSL_CTX() using
	   CTX_set_tlsext_servername_callback();

	   The callback function is required to retrieve the client-supplied servername with
	   get_servername(ssl). Figure out the right SSL_CTX to go with that host name, then
	   switch the SSL object to that SSL_CTX with set_SSL_CTX().

	   Example:

	    # set callback
	    Net::SSLeay::CTX_set_tlsext_servername_callback($ctx,
	       sub {
		 my $ssl = shift;
		 my $h = Net::SSLeay::get_servername($ssl);
		 Net::SSLeay::set_SSL_CTX($ssl, $hostnames{$h}->{ctx}) if exists $hostnames{$h};
	       } );

	   More complete example:

	    # ... initialize Net::SSLeay

	    my %hostnames = (
	      'sni1' => { cert=>'sni1.pem', key=>'sni1.key' },
	      'sni2' => { cert=>'sni2.pem', key=>'sni2.key' },
	    );

	    # create a new context for each certificate/key pair
	    for my $name (keys %hostnames) {
	      $hostnames{$name}->{ctx} = Net::SSLeay::CTX_new or die;
	      Net::SSLeay::CTX_set_cipher_list($hostnames{$name}->{ctx}, 'ALL');
	      Net::SSLeay::set_cert_and_key($hostnames{$name}->{ctx},
	      $hostnames{$name}->{cert}, $hostnames{$name}->{key}) or die;
	    }

	    # create default context
	    my $ctx = Net::SSLeay::CTX_new or die;
	    Net::SSLeay::CTX_set_cipher_list($ctx, 'ALL');
	    Net::SSLeay::set_cert_and_key($ctx, 'cert.pem','key.pem') or die;

	    # set callback
	    Net::SSLeay::CTX_set_tlsext_servername_callback($ctx, sub {
	      my $ssl = shift;
	      my $h = Net::SSLeay::get_servername($ssl);
	      Net::SSLeay::set_SSL_CTX($ssl, $hostnames{$h}->{ctx}) if exists $hostnames{$h};
	      } );

	    # ... later

	    $s = Net::SSLeay::new($ctx);
	    Net::SSLeay::set_fd($s, fileno($accepted_socket));
	    Net::SSLeay::accept($s);

       Low level API: NPN (next protocol negotiation) related functions

       Simple approach for using NPN support looks like this:

	### client side
	use Net::SSLeay;
	use IO::Socket::INET;

	Net::SSLeay::initialize();
	my $sock = IO::Socket::INET->new(PeerAddr=>'encrypted.google.com:443') or die;
	my $ctx = Net::SSLeay::CTX_tlsv1_new() or die;
	Net::SSLeay::CTX_set_options($ctx, &Net::SSLeay::OP_ALL);
	Net::SSLeay::CTX_set_next_proto_select_cb($ctx, ['http1.1','spdy/2']);
	my $ssl = Net::SSLeay::new($ctx) or die;
	Net::SSLeay::set_fd($ssl, fileno($sock)) or die;
	Net::SSLeay::connect($ssl);

	warn "client:negotiated=",Net::SSLeay::P_next_proto_negotiated($ssl), "\n";
	warn "client:last_status=", Net::SSLeay::P_next_proto_last_status($ssl), "\n";

	### server side
	use Net::SSLeay;
	use IO::Socket::INET;

	Net::SSLeay::initialize();
	my $ctx = Net::SSLeay::CTX_tlsv1_new() or die;
	Net::SSLeay::CTX_set_options($ctx, &Net::SSLeay::OP_ALL);
	Net::SSLeay::set_cert_and_key($ctx, "t/data/cert.pem", "t/data/key.pem");
	Net::SSLeay::CTX_set_next_protos_advertised_cb($ctx, ['spdy/2','http1.1']);
	my $sock = IO::Socket::INET->new(LocalAddr=>'localhost', LocalPort=>5443, Proto=>'tcp', Listen=>20) or die;

	while(1) {
	  my $ssl = Net::SSLeay::new($ctx);
	  warn("server:waiting for incoming connection...\n");
	  my $fd = $sock->accept();
	  Net::SSLeay::set_fd($ssl, $fd->fileno);
	  Net::SSLeay::accept($ssl);
	  warn "server:negotiated=",Net::SSLeay::P_next_proto_negotiated($ssl),"\n";
	  my $got = Net::SSLeay::read($ssl);
	  Net::SSLeay::ssl_write_all($ssl, "length=".length($got));
	  Net::SSLeay::free($ssl);
	  $fd->close();
	}
	# check with: openssl s_client -connect localhost:5443 -nextprotoneg http/1.1,spdy/2

       Please note that the selection (negotiation) is performed by client side, the server side
       simply advertise the list of supported protocols.

       Advanced approach allows you to implement your own negotiation algorithm.

	#see below documentation for:
	Net::SSleay::CTX_set_next_proto_select_cb($ctx, $perl_callback_function, $callback_data);
	Net::SSleay::CTX_set_next_protos_advertised_cb($ctx, $perl_callback_function, $callback_data);

       Detection of NPN support (works even in older Net::SSLeay versions):

	use Net::SSLeay;

	if (exists &Net::SSLeay::P_next_proto_negotiated) {
	  # do NPN stuff
	}

       o   CTX_set_next_proto_select_cb

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before; requires at least
	   openssl-1.0.1

	   NOTE: You need CTX_set_next_proto_select_cb on client side of SSL connection.

	   Simple usage - in this case a "common" negotiation algorithm (as implemented by
	   openssl's function SSL_select_next_proto) is used.

	    $rv = Net::SSleay::CTX_set_next_proto_select_cb($ctx, $arrayref);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $arrayref - list of accepted protocols - e.g. ['http1.0', 'http1.1']
	    #
	    # returns: 0 on success, 1 on failure

	   Advanced usage (you probably do not need this):

	    $rv = Net::SSleay::CTX_set_next_proto_select_cb($ctx, $perl_callback_function, $callback_data);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $perl_callback_function - reference to perl function
	    # $callback_data - [optional] data to passed to callback function when invoked
	    #
	    # returns: 0 on success, 1 on failure

	    # where callback function looks like
	    sub npn_advertised_cb_invoke {
	      my ($ssl, $arrayref_proto_list_advertised_by_server, $callback_data) = @_;
	      my $status;
	      # ...
	      $status = 1;   #status can be:
			     # 0 - OPENSSL_NPN_UNSUPPORTED
			     # 1 - OPENSSL_NPN_NEGOTIATED
			     # 2 - OPENSSL_NPN_NO_OVERLAP
	      return $status, ['http1.1','spdy/2']; # the callback has to return 2 values
	    }

	   To undefine/clear this callback use:

	    Net::SSleay::CTX_set_next_proto_select_cb($ctx, undef);

       o   CTX_set_next_protos_advertised_cb

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before; requires at least
	   openssl-1.0.1

	   NOTE: You need CTX_set_next_proto_select_cb on server side of SSL connection.

	   Simple usage:

	    $rv = Net::SSleay::CTX_set_next_protos_advertised_cb($ctx, $arrayref);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $arrayref - list of advertised protocols - e.g. ['http1.0', 'http1.1']
	    #
	    # returns: 0 on success, 1 on failure

	   Advanced usage (you probably do not need this):

	    $rv = Net::SSleay::CTX_set_next_protos_advertised_cb($ctx, $perl_callback_function, $callback_data);
	    # $ctx - value corresponding to openssl's SSL_CTX structure
	    # $perl_callback_function - reference to perl function
	    # $callback_data - [optional] data to passed to callback function when invoked
	    #
	    # returns: 0 on success, 1 on failure

	    # where callback function looks like
	    sub npn_advertised_cb_invoke {
	      my ($ssl, $callback_data) = @_;
	      # ...
	      return ['http1.1','spdy/2']; # the callback has to return arrayref
	    }

	   To undefine/clear this callback use:

	    Net::SSleay::CTX_set_next_protos_advertised_cb($ctx, undef);

       o   P_next_proto_negotiated

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before; requires at least
	   openssl-1.0.1

	   Returns the name of negotiated protocol for given SSL connection $ssl.

	    $rv = Net::SSLeay::P_next_proto_negotiated($ssl)
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: (string) negotiated protocol name (or undef if no negotiation was done or failed with fatal error)

       o   P_next_proto_last_status

	   COMPATIBILITY: not available in Net-SSLeay-1.45 and before; requires at least
	   openssl-1.0.1

	   Returns the result of the last negotiation for given SSL connection $ssl.

	    $rv = Net::SSLeay::P_next_proto_last_status($ssl)
	    # $ssl - value corresponding to openssl's SSL structure
	    #
	    # returns: (integer) negotiation status
	    #	       0 - OPENSSL_NPN_UNSUPPORTED
	    #	       1 - OPENSSL_NPN_NEGOTIATED
	    #	       2 - OPENSSL_NPN_NO_OVERLAP

       Low level API: DANE Support

       OpenSSL version 1.0.2 adds preliminary support RFC6698 Domain Authentication of Named
       Entities (DANE) Transport Layer Association within OpenSSL

       o   SSL_get_tlsa_record_byname

	   COMPATIBILITY: Requires at least openssl-1.0.2

	   In order to facilitate DANE there is additional interface, SSL_get_tlsa_record_byname,
	   accepting hostname, port and socket type that returns packed TLSA record. In order to
	   make it even easier there is additional SSL_ctrl function that calls
	   SSL_get_tlsa_record_byname for you. Latter is recommended for programmers that wish to
	   maintain broader binary compatibility, e.g. make application work with both 1.0.2 and
	   prior version (in which case call to SSL_ctrl with new code returning error would have
	   to be ignored when running with prior version).

	   Net::SSLeay::get_tlsa_record_byname($name, $port, $type);

       Low level API: Other functions

       o   COMP_add_compression_method

	   Adds the compression method cm with the identifier id to the list of available
	   compression methods.  This list is globally maintained for all SSL operations within
	   this application.  It cannot be set for specific SSL_CTX or SSL objects.

	    my $rv = Net::SSLeay::COMP_add_compression_method($id, $cm);
	    # $id - (integer) compression method id
	    #	    0 to 63:	methods defined by the IETF
	    #	    64 to 192:	external party methods assigned by IANA
	    #	    193 to 255: reserved for private use
	    #
	    # $cm - value corresponding to openssl's COMP_METHOD structure
	    #
	    # returns: 0 on success, 1 on failure (check the error queue to find out the reason)

	   Check openssl doc
	   <http://www.openssl.org/docs/ssl/SSL_COMP_add_compression_method.html>

       o   DH_free

	   Frees the DH structure and its components. The values are erased before the memory is
	   returned to the system.

	    Net::SSLeay::DH_free($dh);
	    # $dh - value corresponding to openssl's DH structure
	    #
	    # returns: no return value

	   Check openssl doc <http://www.openssl.org/docs/crypto/DH_new.html>

       o   FIPS_mode_set

	   Enable or disable FIPS mode in a FIPS capable OpenSSL.

	    Net::SSLeay:: FIPS_mode_set($enable);
	    # $enable - (integer) 1 to enable, 0 to disable

   Constants
       There are many openssl constants available in Net::SSLeay. You can use them like this:

	use Net::SSLeay;
	print &Net::SSLeay::NID_commonName;
	#or
	print Net::SSLeay::NID_commonName();

       Or you can import them and use:

	use Net::SSLeay qw/NID_commonName/;
	print &NID_commonName;
	#or
	print NID_commonName();
	#or
	print NID_commonName;

       The constants names are derived from openssl constants, however constants starting with
       "SSL_" prefix have name with "SSL_" part stripped - e.g. openssl's constant "SSL_OP_ALL"
       is available as "Net::SSleay::OP_ALL"

       The list of all available constant names:

	ASN1_STRFLGS_ESC_CTRL		NID_ext_req			       OP_CISCO_ANYCONNECT
	ASN1_STRFLGS_ESC_MSB		NID_friendlyName		       OP_COOKIE_EXCHANGE
	ASN1_STRFLGS_ESC_QUOTE		NID_givenName			       OP_CRYPTOPRO_TLSEXT_BUG
	ASN1_STRFLGS_RFC2253		NID_hmacWithSHA1		       OP_DONT_INSERT_EMPTY_FRAGMENTS
	CB_ACCEPT_EXIT			NID_id_ad			       OP_EPHEMERAL_RSA
	CB_ACCEPT_LOOP			NID_id_ce			       OP_LEGACY_SERVER_CONNECT
	CB_CONNECT_EXIT 		NID_id_kp			       OP_MICROSOFT_BIG_SSLV3_BUFFER
	CB_CONNECT_LOOP 		NID_id_pbkdf2			       OP_MICROSOFT_SESS_ID_BUG
	ERROR_NONE			NID_id_pe			       OP_MSIE_SSLV2_RSA_PADDING
	ERROR_SSL			NID_id_pkix			       OP_NETSCAPE_CA_DN_BUG
	ERROR_SYSCALL			NID_id_qt_cps			       OP_NETSCAPE_CHALLENGE_BUG
	ERROR_WANT_ACCEPT		NID_id_qt_unotice		       OP_NETSCAPE_DEMO_CIPHER_CHANGE_BUG
	ERROR_WANT_CONNECT		NID_idea_cbc			       OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG
	ERROR_WANT_READ 		NID_idea_cfb64			       OP_NON_EXPORT_FIRST
	ERROR_WANT_WRITE		NID_idea_ecb			       OP_NO_COMPRESSION
	ERROR_WANT_X509_LOOKUP		NID_idea_ofb64			       OP_NO_QUERY_MTU
	ERROR_ZERO_RETURN		NID_info_access 		       OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION
	EVP_PKS_DSA			NID_initials			       OP_NO_SSLv2
	EVP_PKS_EC			NID_invalidity_date		       OP_NO_SSLv3
	EVP_PKS_RSA			NID_issuer_alt_name		       OP_NO_TICKET
	EVP_PKT_ENC			NID_keyBag			       OP_NO_TLSv1
	EVP_PKT_EXCH			NID_key_usage			       OP_NO_TLSv1_1
	EVP_PKT_EXP			NID_localKeyID			       OP_NO_TLSv1_2
	EVP_PKT_SIGN			NID_localityName		       OP_PKCS1_CHECK_1
	EVP_PK_DH			NID_md2 			       OP_PKCS1_CHECK_2
	EVP_PK_DSA			NID_md2WithRSAEncryption	       OP_SINGLE_DH_USE
	EVP_PK_EC			NID_md5 			       OP_SINGLE_ECDH_USE
	EVP_PK_RSA			NID_md5WithRSA			       OP_SSLEAY_080_CLIENT_DH_BUG
	FILETYPE_ASN1			NID_md5WithRSAEncryption	       OP_SSLREF2_REUSE_CERT_TYPE_BUG
	FILETYPE_PEM			NID_md5_sha1			       OP_TLS_BLOCK_PADDING_BUG
	F_CLIENT_CERTIFICATE		NID_mdc2			       OP_TLS_D5_BUG
	F_CLIENT_HELLO			NID_mdc2WithRSA 		       OP_TLS_ROLLBACK_BUG
	F_CLIENT_MASTER_KEY		NID_ms_code_com 		       READING
	F_D2I_SSL_SESSION		NID_ms_code_ind 		       RECEIVED_SHUTDOWN
	F_GET_CLIENT_FINISHED		NID_ms_ctl_sign 		       RSA_3
	F_GET_CLIENT_HELLO		NID_ms_efs			       RSA_F4
	F_GET_CLIENT_MASTER_KEY 	NID_ms_ext_req			       R_BAD_AUTHENTICATION_TYPE
	F_GET_SERVER_FINISHED		NID_ms_sgc			       R_BAD_CHECKSUM
	F_GET_SERVER_HELLO		NID_name			       R_BAD_MAC_DECODE
	F_GET_SERVER_VERIFY		NID_netscape			       R_BAD_RESPONSE_ARGUMENT
	F_I2D_SSL_SESSION		NID_netscape_base_url		       R_BAD_SSL_FILETYPE
	F_READ_N			NID_netscape_ca_policy_url	       R_BAD_SSL_SESSION_ID_LENGTH
	F_REQUEST_CERTIFICATE		NID_netscape_ca_revocation_url	       R_BAD_STATE
	F_SERVER_HELLO			NID_netscape_cert_extension	       R_BAD_WRITE_RETRY
	F_SSL_CERT_NEW			NID_netscape_cert_sequence	       R_CHALLENGE_IS_DIFFERENT
	F_SSL_GET_NEW_SESSION		NID_netscape_cert_type		       R_CIPHER_TABLE_SRC_ERROR
	F_SSL_NEW			NID_netscape_comment		       R_INVALID_CHALLENGE_LENGTH
	F_SSL_READ			NID_netscape_data_type		       R_NO_CERTIFICATE_SET
	F_SSL_RSA_PRIVATE_DECRYPT	NID_netscape_renewal_url	       R_NO_CERTIFICATE_SPECIFIED
	F_SSL_RSA_PUBLIC_ENCRYPT	NID_netscape_revocation_url	       R_NO_CIPHER_LIST
	F_SSL_SESSION_NEW		NID_netscape_ssl_server_name	       R_NO_CIPHER_MATCH
	F_SSL_SESSION_PRINT_FP		NID_ns_sgc			       R_NO_PRIVATEKEY
	F_SSL_SET_FD			NID_organizationName		       R_NO_PUBLICKEY
	F_SSL_SET_RFD			NID_organizationalUnitName	       R_NULL_SSL_CTX
	F_SSL_SET_WFD			NID_pbeWithMD2AndDES_CBC	       R_PEER_DID_NOT_RETURN_A_CERTIFICATE
	F_SSL_USE_CERTIFICATE		NID_pbeWithMD2AndRC2_CBC	       R_PEER_ERROR
	F_SSL_USE_CERTIFICATE_ASN1	NID_pbeWithMD5AndCast5_CBC	       R_PEER_ERROR_CERTIFICATE
	F_SSL_USE_CERTIFICATE_FILE	NID_pbeWithMD5AndDES_CBC	       R_PEER_ERROR_NO_CIPHER
	F_SSL_USE_PRIVATEKEY		NID_pbeWithMD5AndRC2_CBC	       R_PEER_ERROR_UNSUPPORTED_CERTIFICATE_TYPE
	F_SSL_USE_PRIVATEKEY_ASN1	NID_pbeWithSHA1AndDES_CBC	       R_PUBLIC_KEY_ENCRYPT_ERROR
	F_SSL_USE_PRIVATEKEY_FILE	NID_pbeWithSHA1AndRC2_CBC	       R_PUBLIC_KEY_IS_NOT_RSA
	F_SSL_USE_RSAPRIVATEKEY 	NID_pbe_WithSHA1And128BitRC2_CBC       R_READ_WRONG_PACKET_TYPE
	F_SSL_USE_RSAPRIVATEKEY_ASN1	NID_pbe_WithSHA1And128BitRC4	       R_SHORT_READ
	F_SSL_USE_RSAPRIVATEKEY_FILE	NID_pbe_WithSHA1And2_Key_TripleDES_CBC R_SSL_SESSION_ID_IS_DIFFERENT
	F_WRITE_PENDING 		NID_pbe_WithSHA1And3_Key_TripleDES_CBC R_UNABLE_TO_EXTRACT_PUBLIC_KEY
	GEN_DIRNAME			NID_pbe_WithSHA1And40BitRC2_CBC        R_UNKNOWN_REMOTE_ERROR_TYPE
	GEN_DNS 			NID_pbe_WithSHA1And40BitRC4	       R_UNKNOWN_STATE
	GEN_EDIPARTY			NID_pbes2			       R_X509_LIB
	GEN_EMAIL			NID_pbmac1			       SENT_SHUTDOWN
	GEN_IPADD			NID_pkcs			       SESSION_ASN1_VERSION
	GEN_OTHERNAME			NID_pkcs3			       ST_ACCEPT
	GEN_RID 			NID_pkcs7			       ST_BEFORE
	GEN_URI 			NID_pkcs7_data			       ST_CONNECT
	GEN_X400			NID_pkcs7_digest		       ST_INIT
	MBSTRING_ASC			NID_pkcs7_encrypted		       ST_OK
	MBSTRING_BMP			NID_pkcs7_enveloped		       ST_READ_BODY
	MBSTRING_FLAG			NID_pkcs7_signed		       ST_READ_HEADER
	MBSTRING_UNIV			NID_pkcs7_signedAndEnveloped	       VERIFY_CLIENT_ONCE
	MBSTRING_UTF8			NID_pkcs8ShroudedKeyBag 	       VERIFY_FAIL_IF_NO_PEER_CERT
	MIN_RSA_MODULUS_LENGTH_IN_BYTES NID_pkcs9			       VERIFY_NONE
	MODE_ACCEPT_MOVING_WRITE_BUFFER NID_pkcs9_challengePassword	       VERIFY_PEER
	MODE_AUTO_RETRY 		NID_pkcs9_contentType		       WRITING
	MODE_ENABLE_PARTIAL_WRITE	NID_pkcs9_countersignature	       X509_LOOKUP
	MODE_RELEASE_BUFFERS		NID_pkcs9_emailAddress		       X509_PURPOSE_ANY
	NID_OCSP_sign			NID_pkcs9_extCertAttributes	       X509_PURPOSE_CRL_SIGN
	NID_SMIMECapabilities		NID_pkcs9_messageDigest 	       X509_PURPOSE_NS_SSL_SERVER
	NID_X500			NID_pkcs9_signingTime		       X509_PURPOSE_OCSP_HELPER
	NID_X509			NID_pkcs9_unstructuredAddress	       X509_PURPOSE_SMIME_ENCRYPT
	NID_ad_OCSP			NID_pkcs9_unstructuredName	       X509_PURPOSE_SMIME_SIGN
	NID_ad_ca_issuers		NID_private_key_usage_period	       X509_PURPOSE_SSL_CLIENT
	NID_algorithm			NID_rc2_40_cbc			       X509_PURPOSE_SSL_SERVER
	NID_authority_key_identifier	NID_rc2_64_cbc			       X509_PURPOSE_TIMESTAMP_SIGN
	NID_basic_constraints		NID_rc2_cbc			       X509_TRUST_COMPAT
	NID_bf_cbc			NID_rc2_cfb64			       X509_TRUST_EMAIL
	NID_bf_cfb64			NID_rc2_ecb			       X509_TRUST_OBJECT_SIGN
	NID_bf_ecb			NID_rc2_ofb64			       X509_TRUST_OCSP_REQUEST
	NID_bf_ofb64			NID_rc4 			       X509_TRUST_OCSP_SIGN
	NID_cast5_cbc			NID_rc4_40			       X509_TRUST_SSL_CLIENT
	NID_cast5_cfb64 		NID_rc5_cbc			       X509_TRUST_SSL_SERVER
	NID_cast5_ecb			NID_rc5_cfb64			       X509_TRUST_TSA
	NID_cast5_ofb64 		NID_rc5_ecb			       X509_V_FLAG_ALLOW_PROXY_CERTS
	NID_certBag			NID_rc5_ofb64			       X509_V_FLAG_CB_ISSUER_CHECK
	NID_certificate_policies	NID_ripemd160			       X509_V_FLAG_CHECK_SS_SIGNATURE
	NID_client_auth 		NID_ripemd160WithRSA		       X509_V_FLAG_CRL_CHECK
	NID_code_sign			NID_rle_compression		       X509_V_FLAG_CRL_CHECK_ALL
	NID_commonName			NID_rsa 			       X509_V_FLAG_EXPLICIT_POLICY
	NID_countryName 		NID_rsaEncryption		       X509_V_FLAG_EXTENDED_CRL_SUPPORT
	NID_crlBag			NID_rsadsi			       X509_V_FLAG_IGNORE_CRITICAL
	NID_crl_distribution_points	NID_safeContentsBag		       X509_V_FLAG_INHIBIT_ANY
	NID_crl_number			NID_sdsiCertificate		       X509_V_FLAG_INHIBIT_MAP
	NID_crl_reason			NID_secretBag			       X509_V_FLAG_NOTIFY_POLICY
	NID_delta_crl			NID_serialNumber		       X509_V_FLAG_POLICY_CHECK
	NID_des_cbc			NID_server_auth 		       X509_V_FLAG_POLICY_MASK
	NID_des_cfb64			NID_sha 			       X509_V_FLAG_USE_CHECK_TIME
	NID_des_ecb			NID_sha1			       X509_V_FLAG_USE_DELTAS
	NID_des_ede			NID_sha1WithRSA 		       X509_V_FLAG_X509_STRICT
	NID_des_ede3			NID_sha1WithRSAEncryption	       X509_V_OK
	NID_des_ede3_cbc		NID_shaWithRSAEncryption	       XN_FLAG_COMPAT
	NID_des_ede3_cfb64		NID_stateOrProvinceName 	       XN_FLAG_DN_REV
	NID_des_ede3_ofb64		NID_subject_alt_name		       XN_FLAG_DUMP_UNKNOWN_FIELDS
	NID_des_ede_cbc 		NID_subject_key_identifier	       XN_FLAG_FN_ALIGN
	NID_des_ede_cfb64		NID_surname			       XN_FLAG_FN_LN
	NID_des_ede_ofb64		NID_sxnet			       XN_FLAG_FN_MASK
	NID_des_ofb64			NID_time_stamp			       XN_FLAG_FN_NONE
	NID_description 		NID_title			       XN_FLAG_FN_OID
	NID_desx_cbc			NID_undef			       XN_FLAG_FN_SN
	NID_dhKeyAgreement		NID_uniqueIdentifier		       XN_FLAG_MULTILINE
	NID_dnQualifier 		NID_x509Certificate		       XN_FLAG_ONELINE
	NID_dsa 			NID_x509Crl			       XN_FLAG_RFC2253
	NID_dsaWithSHA			NID_zlib_compression		       XN_FLAG_SEP_COMMA_PLUS
	NID_dsaWithSHA1 		NOTHING 			       XN_FLAG_SEP_CPLUS_SPC
	NID_dsaWithSHA1_2		OPENSSL_VERSION_NUMBER		       XN_FLAG_SEP_MASK
	NID_dsa_2			OP_ALL				       XN_FLAG_SEP_MULTILINE
	NID_email_protect		OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION   XN_FLAG_SEP_SPLUS_SPC
	NID_ext_key_usage		OP_CIPHER_SERVER_PREFERENCE	       XN_FLAG_SPC_EQ

   INTERNAL ONLY functions (do not use these)
       The following functions are not intended for use from outside of Net::SSLeay module.  They
       might be removed, renamed or changed without prior notice in future version.

       Simply DO NOT USE THEM!

       o   hello

       o   blength

       o   constant

EXAMPLES
       One very good example to look at is the implementation of "sslcat()" in the "SSLeay.pm"
       file.

       The following is a simple SSLeay client (with too little error checking :-(

	   #!/usr/bin/perl
	   use Socket;
	   use Net::SSLeay qw(die_now die_if_ssl_error) ;
	   Net::SSLeay::load_error_strings();
	   Net::SSLeay::SSLeay_add_ssl_algorithms();
	   Net::SSLeay::randomize();

	   ($dest_serv, $port, $msg) = @ARGV;	   # Read command line
	   $port = getservbyname ($port, 'tcp') unless $port =~ /^\d+$/;
	   $dest_ip = gethostbyname ($dest_serv);
	   $dest_serv_params  = sockaddr_in($port, $dest_ip);

	   socket  (S, &AF_INET, &SOCK_STREAM, 0)  or die "socket: $!";
	   connect (S, $dest_serv_params)	   or die "connect: $!";
	   select  (S); $| = 1; select (STDOUT);   # Eliminate STDIO buffering

	   # The network connection is now open, lets fire up SSL

	   $ctx = Net::SSLeay::CTX_new() or die_now("Failed to create SSL_CTX $!");
	   Net::SSLeay::CTX_set_options($ctx, &Net::SSLeay::OP_ALL)
		or die_if_ssl_error("ssl ctx set options");
	   $ssl = Net::SSLeay::new($ctx) or die_now("Failed to create SSL $!");
	   Net::SSLeay::set_fd($ssl, fileno(S));   # Must use fileno
	   $res = Net::SSLeay::connect($ssl) and die_if_ssl_error("ssl connect");
	   print "Cipher `" . Net::SSLeay::get_cipher($ssl) . "'\n";

	   # Exchange data

	   $res = Net::SSLeay::write($ssl, $msg);  # Perl knows how long $msg is
	   die_if_ssl_error("ssl write");
	   CORE::shutdown S, 1;  # Half close --> No more output, sends EOF to server
	   $got = Net::SSLeay::read($ssl);	   # Perl returns undef on failure
	   die_if_ssl_error("ssl read");
	   print $got;

	   Net::SSLeay::free ($ssl);		   # Tear down connection
	   Net::SSLeay::CTX_free ($ctx);
	   close S;

       The following is a simple SSLeay echo server (non forking):

	   #!/usr/bin/perl -w
	   use Socket;
	   use Net::SSLeay qw(die_now die_if_ssl_error);
	   Net::SSLeay::load_error_strings();
	   Net::SSLeay::SSLeay_add_ssl_algorithms();
	   Net::SSLeay::randomize();

	   $our_ip = "\0\0\0\0"; # Bind to all interfaces
	   $port = 1235;
	   $sockaddr_template = 'S n a4 x8';
	   $our_serv_params = pack ($sockaddr_template, &AF_INET, $port, $our_ip);

	   socket (S, &AF_INET, &SOCK_STREAM, 0)  or die "socket: $!";
	   bind (S, $our_serv_params)		  or die "bind:   $!";
	   listen (S, 5)			  or die "listen: $!";
	   $ctx = Net::SSLeay::CTX_new ()	  or die_now("CTX_new ($ctx): $!");
	   Net::SSLeay::CTX_set_options($ctx, &Net::SSLeay::OP_ALL)
		or die_if_ssl_error("ssl ctx set options");

	   # Following will ask password unless private key is not encrypted
	   Net::SSLeay::CTX_use_RSAPrivateKey_file ($ctx, 'plain-rsa.pem',
						    &Net::SSLeay::FILETYPE_PEM);
	   die_if_ssl_error("private key");
	   Net::SSLeay::CTX_use_certificate_file ($ctx, 'plain-cert.pem',
						  &Net::SSLeay::FILETYPE_PEM);
	   die_if_ssl_error("certificate");

	   while(1) {
	       print "Accepting connections...\n";
	       ($addr = accept (NS, S)) 	  or die "accept: $!";
	       select (NS); $| = 1; select (STDOUT);  # Piping hot!

	       ($af,$client_port,$client_ip) = unpack($sockaddr_template,$addr);
	       @inetaddr = unpack('C4',$client_ip);
	       print "$af connection from " .
	       join ('.', @inetaddr) . ":$client_port\n";

	       # We now have a network connection, lets fire up SSLeay...

	       $ssl = Net::SSLeay::new($ctx)	  or die_now("SSL_new ($ssl): $!");
	       Net::SSLeay::set_fd($ssl, fileno(NS));

	       $err = Net::SSLeay::accept($ssl) and die_if_ssl_error('ssl accept');
	       print "Cipher `" . Net::SSLeay::get_cipher($ssl) . "'\n";

	       # Connected. Exchange some data.

	       $got = Net::SSLeay::read($ssl);	   # Returns undef on fail
	       die_if_ssl_error("ssl read");
	       print "Got `$got' (" . length ($got) . " chars)\n";

	       Net::SSLeay::write ($ssl, uc ($got)) or die "write: $!";
	       die_if_ssl_error("ssl write");

	       Net::SSLeay::free ($ssl);	   # Tear down connection
	       close NS;
	   }

       Yet another echo server. This one runs from "/etc/inetd.conf" so it avoids all the socket
       code overhead. Only caveat is opening an rsa key file - it had better be without any
       encryption or else it will not know where to ask for the password. Note how "STDIN" and
       "STDOUT" are wired to SSL.

	   #!/usr/bin/perl
	   # /etc/inetd.conf
	   #	ssltst stream tcp nowait root /path/to/server.pl server.pl
	   # /etc/services
	   #	ssltst	       1234/tcp

	   use Net::SSLeay qw(die_now die_if_ssl_error);
	   Net::SSLeay::load_error_strings();
	   Net::SSLeay::SSLeay_add_ssl_algorithms();
	   Net::SSLeay::randomize();

	   chdir '/key/dir' or die "chdir: $!";
	   $| = 1;  # Piping hot!
	   open LOG, ">>/dev/console" or die "Can't open log file $!";
	   select LOG; print "server.pl started\n";

	   $ctx = Net::SSLeay::CTX_new()     or die_now "CTX_new ($ctx) ($!)";
	   $ssl = Net::SSLeay::new($ctx)     or die_now "new ($ssl) ($!)";
	   Net::SSLeay::set_options($ssl, &Net::SSLeay::OP_ALL)
		and die_if_ssl_error("ssl set options");

	   # We get already open network connection from inetd, now we just
	   # need to attach SSLeay to STDIN and STDOUT
	   Net::SSLeay::set_rfd($ssl, fileno(STDIN));
	   Net::SSLeay::set_wfd($ssl, fileno(STDOUT));

	   Net::SSLeay::use_RSAPrivateKey_file ($ssl, 'plain-rsa.pem',
						Net::SSLeay::FILETYPE_PEM);
	   die_if_ssl_error("private key");
	   Net::SSLeay::use_certificate_file ($ssl, 'plain-cert.pem',
					      Net::SSLeay::FILETYPE_PEM);
	   die_if_ssl_error("certificate");

	   Net::SSLeay::accept($ssl) and die_if_ssl_err("ssl accept: $!");
	   print "Cipher `" . Net::SSLeay::get_cipher($ssl) . "'\n";

	   $got = Net::SSLeay::read($ssl);
	   die_if_ssl_error("ssl read");
	   print "Got `$got' (" . length ($got) . " chars)\n";

	   Net::SSLeay::write ($ssl, uc($got)) or die "write: $!";
	   die_if_ssl_error("ssl write");

	   Net::SSLeay::free ($ssl);	     # Tear down the connection
	   Net::SSLeay::CTX_free ($ctx);
	   close LOG;

       There are also a number of example/test programs in the examples directory:

	   sslecho.pl	-  A simple server, not unlike the one above
	   minicli.pl	-  Implements a client using low level SSLeay routines
	   sslcat.pl	-  Demonstrates using high level sslcat utility function
	   get_page.pl	-  Is a utility for getting html pages from secure servers
	   callback.pl	-  Demonstrates certificate verification and callback usage
	   stdio_bulk.pl       - Does SSL over Unix pipes
	   ssl-inetd-serv.pl   - SSL server that can be invoked from inetd.conf
	   httpd-proxy-snif.pl - Utility that allows you to see how a browser
				 sends https request to given server and what reply
				 it gets back (very educative :-)
	   makecert.pl	-  Creates a self signed cert (does not use this module)

LIMITATIONS
       "Net::SSLeay::read()" uses an internal buffer of 32KB, thus no single read will return
       more. In practice one read returns much less, usually as much as fits in one network
       packet. To work around this, you should use a loop like this:

	   $reply = '';
	   while ($got = Net::SSLeay::read($ssl)) {
	       last if print_errs('SSL_read');
	       $reply .= $got;
	   }

       Although there is no built-in limit in "Net::SSLeay::write()", the network packet size
       limitation applies here as well, thus use:

	   $written = 0;

	   while ($written < length($message)) {
	       $written += Net::SSLeay::write($ssl, substr($message, $written));
	       last if print_errs('SSL_write');
	   }

       Or alternatively you can just use the following convenience functions:

	   Net::SSLeay::ssl_write_all($ssl, $message) or die "ssl write failure";
	   $got = Net::SSLeay::ssl_read_all($ssl) or die "ssl read failure";

KNOWN BUGS AND CAVEATS
       Autoloader emits a

	   Argument "xxx" isn't numeric in entersub at blib/lib/Net/SSLeay.pm'

       warning if die_if_ssl_error is made autoloadable. If you figure out why, drop me a line.

       Callback set using "SSL_set_verify()" does not appear to work. This may well be an openssl
       problem (e.g. see "ssl/ssl_lib.c" line 1029). Try using "SSL_CTX_set_verify()" instead and
       do not be surprised if even this stops working in future versions.

       Callback and certificate verification stuff is generally too little tested.

       Random numbers are not initialized randomly enough, especially if you do not have
       "/dev/random" and/or "/dev/urandom" (such as in Solaris platforms - but it's been
       suggested that cryptorand daemon from the SUNski package solves this). In this case you
       should investigate third party software that can emulate these devices, e.g. by way of a
       named pipe to some program.

       Another gotcha with random number initialization is randomness depletion. This phenomenon,
       which has been extensively discussed in OpenSSL, Apache-SSL, and Apache-mod_ssl forums,
       can cause your script to block if you use "/dev/random" or to operate insecurely if you
       use "/dev/urandom". What happens is that when too much randomness is drawn from the
       operating system's randomness pool then randomness can temporarily be unavailable.
       "/dev/random" solves this problem by waiting until enough randomness can be gathered - and
       this can take a long time since blocking reduces activity in the machine and less activity
       provides less random events: a vicious circle.  "/dev/urandom" solves this dilemma more
       pragmatically by simply returning predictable "random" numbers. Some" /dev/urandom"
       emulation software however actually seems to implement "/dev/random" semantics. Caveat
       emptor.

       I've been pointed to two such daemons by Mik Firestone <mik@@speed.stdio._com> who has
       used them on Solaris 8:

       1.  Entropy Gathering Daemon (EGD) at <http://www.lothar.com/tech/crypto/>

       2.  Pseudo-random number generating daemon (PRNGD) at
	   <http://www.aet.tu-cottbus.de/personen/jaenicke/postfix_tls/prngd.html>

       If you are using the low level API functions to communicate with other SSL
       implementations, you would do well to call

	   Net::SSLeay::CTX_set_options($ctx, &Net::SSLeay::OP_ALL)
		or die_if_ssl_error("ssl ctx set options");

       to cope with some well know bugs in some other SSL implementations. The high level API
       functions always set all known compatibility options.

       Sometimes "sslcat()" (and the high level HTTPS functions that build on it) is too fast in
       signaling the EOF to legacy HTTPS servers. This causes the server to return empty page. To
       work around this problem you can set the global variable

	   $Net::SSLeay::slowly = 1;   # Add sleep so broken servers can keep up

       HTTP/1.1 is not supported. Specifically this module does not know to issue or serve
       multiple http requests per connection. This is a serious shortcoming, but using the SSL
       session cache on your server helps to alleviate the CPU load somewhat.

       As of version 1.09 many newer OpenSSL auxiliary functions were added (from
       "REM_AUTOMATICALLY_GENERATED_1_09" onwards in "SSLeay.xs").  Unfortunately I have not had
       any opportunity to test these. Some of them are trivial enough that I believe they "just
       work", but others have rather complex interfaces with function pointers and all. In these
       cases you should proceed wit great caution.

       This module defaults to using OpenSSL automatic protocol negotiation code for
       automatically detecting the version of the SSL protocol that the other end talks. With
       most web servers this works just fine, but once in a while I get complaints from people
       that the module does not work with some web servers. Usually this can be solved by
       explicitly setting the protocol version, e.g.

	  $Net::SSLeay::ssl_version = 2;  # Insist on SSLv2
	  $Net::SSLeay::ssl_version = 3;  # Insist on SSLv3
	  $Net::SSLeay::ssl_version = 10; # Insist on TLSv1

       Although the autonegotiation is nice to have, the SSL standards do not formally specify
       any such mechanism. Most of the world has accepted the SSLeay/OpenSSL way of doing it as
       the de facto standard. But for the few that think differently, you have to explicitly
       speak the correct version. This is not really a bug, but rather a deficiency in the
       standards. If a site refuses to respond or sends back some nonsensical error codes (at the
       SSL handshake level), try this option before mailing me.

       On some systems, OpenSSL may be compiled without support for SSLv2.  If this is the case,
       Net::SSLeay will warn if ssl_version has been set to 2.

       The high level API returns the certificate of the peer, thus allowing one to check what
       certificate was supplied. However, you will only be able to check the certificate after
       the fact, i.e. you already sent your form data by the time you find out that you did not
       trust them, oops.

       So, while being able to know the certificate after the fact is surely useful, the security
       minded would still choose to do the connection and certificate verification first and only
       then exchange data with the site. Currently none of the high level API functions do this,
       thus you would have to program it using the low level API. A good place to start is to see
       how the "Net::SSLeay::http_cat()" function is implemented.

       The high level API functions use a global file handle "SSLCAT_S" internally. This really
       should not be a problem because there is no way to interleave the high level API
       functions, unless you use threads (but threads are not very well supported in perl anyway
       (as of version 5.6.1). However, you may run into problems if you call undocumented
       internal functions in an interleaved fashion. The best solution is to "require
       Net::SSLeay" in one thread after all the threads have been created.

DIAGNOSTICS
       Random number generator not seeded!!!
	   (W) This warning indicates that "randomize()" was not able to read "/dev/random" or
	   "/dev/urandom", possibly because your system does not have them or they are
	   differently named. You can still use SSL, but the encryption will not be as strong.

       open_tcp_connection: destination host not found:`server' (port 123) ($!)
	   Name lookup for host named "server" failed.

       open_tcp_connection: failed `server', 123 ($!)
	   The name was resolved, but establishing the TCP connection failed.

       msg 123: 1 - error:140770F8:SSL routines:SSL23_GET_SERVER_HELLO:unknown proto
	   SSLeay error string. The first number(123) is the PID, the second number(1)
	   indicates the position of the error message in SSLeay error stack.  You often see a
	   pile of these messages as errors cascade.

       msg 123: 1 - error:02001002::lib(2) :func(1) :reason(2)
	   The same as above, but you didn't call load_error_strings() so SSLeay couldn't
	   verbosely explain the error. You can still find out what it means with this command:

	       /usr/local/ssl/bin/ssleay errstr 02001002

       Password is being asked for private key
	   This is normal behaviour if your private key is encrypted. Either you have to supply
	   the password or you have to use an unencrypted private key. Scan OpenSSL.org for the
	   FAQ that explains how to do this (or just study examples/makecert.pl which is used
	   during "make test" to do just that).

SECURITY
       You can mitigate some of the security vulnerabilites that might be present in your SSL/TLS
       application:

   BEAST Attack
       http://blogs.cisco.com/security/beat-the-beast-with-tls/
       https://community.qualys.com/blogs/securitylabs/2011/10/17/mitigating-the-beast-attack-on-tls
       http://blog.zoller.lu/2011/09/beast-summary-tls-cbc-countermeasures.html

       The BEAST attack relies on a weakness in the way CBC mode is used in SSL/TLS.  In OpenSSL
       versions 0.9.6d and later, the protocol-level mitigation is enabled by default, thus
       making it not vulnerable to the BEAST attack.

       Solutions:

       o   Compile with OpenSSL versions 0.9.6d or later, which enables SSL_OP_ALL by default

       o   Ensure SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS is not enabled (its not enabled by default)

       o   Dont support SSLv2, SSLv3

       o   Actively control the ciphers your server supports with set_cipher_list:

       Net::SSLeay::set_cipher_list($ssl, 'RC4-SHA:HIGH:!ADH');

   Session Resumption
       http://www.openssl.org/docs/ssl/SSL_CTX_set_options.html

       The SSL Labs vulnerability test on your SSL server might report in red:

       Session resumption      No (IDs assigned but not accepted)

       This report is not really bug or a vulnerability, since the server will not accept session
       resumption requests.  However, you can prevent this noise in the report by disabling the
       session cache altogether: Net::SSLeay::CTX_set_session_cache_mode($ssl_ctx, 0);

   Secure Renegotiation and DoS Attack
       https://community.qualys.com/blogs/securitylabs/2011/10/31/tls-renegotiation-and-denial-of-service-attacks

       This is not a "security flaw," it is more of a DoS vulnerability.

       Solutions:

       o   Do not support SSLv2

       o   Do not set the SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION option

       o   Compile with OpenSSL 0.9.8m or later

BUGS AND SUPPORT
       Please report any bugs or feature requests to "bug-Net-SSLeay at rt.cpan.org", or through
       the web interface at <http://rt.cpan.org/Public/Dist/Display.html?Name=Net-SSLeay>.  I
       will be notified, and then you'll automatically be notified of progress on your bug as I
       make changes.

       Subversion access to the latest source code etc can be obtained at
       <http://alioth.debian.org/projects/net-ssleay>

       The developer mailing list (for people interested in contributing to the source code) can
       be found at <http://lists.alioth.debian.org/mailman/listinfo/net-ssleay-devel>

       You can find documentation for this module with the "perldoc" command.

	   perldoc Net::SSLeay

       You can also look for information at:

       o   AnnoCPAN: Annotated CPAN documentation

	   <http://annocpan.org/dist/Net-SSLeay>

       o   CPAN Ratings

	   <http://cpanratings.perl.org/d/Net-SSLeay>

       o   Search CPAN

	   <http://search.cpan.org/dist/Net-SSLeay>

       Commercial support for Net::SSLeay may be obtained from

	  Symlabs (netssleay@symlabs.com)
	  Tel: +351-214.222.630
	  Fax: +351-214.222.637

AUTHOR
       Maintained by Mike McCauley and Florian Ragwitz since November 2005

       Originally written by Sampo Kellomaeki <sampo@symlabs.com>

COPYRIGHT
       Copyright (c) 1996-2003 Sampo Kellomaeki <sampo@symlabs.com>

       Copyright (C) 2005-2006 Florian Ragwitz <rafl@debian.org>

       Copyright (C) 2005 Mike McCauley <mikem@airspayce.com>

       All Rights Reserved.

       Distribution and use of this module is under the same terms as the OpenSSL package itself
       (i.e. free, but mandatory attribution; NO WARRANTY). Please consult LICENSE file in the
       root of the OpenSSL distribution.

       While the source distribution of this perl module does not contain Eric's or OpenSSL's
       code, if you use this module you will use OpenSSL library. Please give Eric and OpenSSL
       team credit (as required by their licenses).

       And remember, you, and nobody else but you, are responsible for auditing this module and
       OpenSSL library for security problems, backdoors, and general suitability for your
       application.

SEE ALSO
	 Net::SSLeay::Handle			  - File handle interface
	 ./examples				  - Example servers and a clients
	 <http://www.openssl.org/>		  - OpenSSL source, documentation, etc
	 openssl-users-request@openssl.org	  - General OpenSSL mailing list
	 <http://www.ietf.org/rfc/rfc2246.txt>	  - TLS 1.0 specification
	 <http://www.w3c.org>			  - HTTP specifications
	 <http://www.ietf.org/rfc/rfc2617.txt>	  - How to send password
	 <http://www.lothar.com/tech/crypto/>	  - Entropy Gathering Daemon (EGD)
	 <http://www.aet.tu-cottbus.de/personen/jaenicke/postfix_tls/prngd.html>
				  - pseudo-random number generating daemon (PRNGD)
	 perl(1)
	 perlref(1)
	 perllol(1)
	 perldoc ~openssl/doc/ssl/SSL_CTX_set_verify.pod

perl v5.16.3				    2013-06-07				   Net::SSLeay(3)


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