
RSA(3) User Contributed Perl Documentation RSA(3)
NAME
Crypt::OpenSSL::RSA  RSA encoding and decoding, using the openSSL libraries
SYNOPSIS
use Crypt::OpenSSL::Random;
use Crypt::OpenSSL::RSA;
# not necessary if we have /dev/random:
Crypt::OpenSSL::Random::random_seed($good_entropy);
Crypt::OpenSSL::RSA>import_random_seed();
$rsa_pub = Crypt::OpenSSL::RSA>new_public_key($key_string);
$rsa_pub>use_sslv23_padding(); # use_pkcs1_oaep_padding is the default
$ciphertext = $rsa>encrypt($plaintext);
$rsa_priv = Crypt::OpenSSL::RSA>new_private_key($key_string);
$plaintext = $rsa>encrypt($ciphertext);
$rsa = Crypt::OpenSSL::RSA>generate_key(1024); # or
$rsa = Crypt::OpenSSL::RSA>generate_key(1024, $prime);
print "private key is:\n", $rsa>get_private_key_string();
print "public key (in PKCS1 format) is:\n",
$rsa>get_public_key_string();
print "public key (in X509 format) is:\n",
$rsa>get_public_key_x509_string();
$rsa_priv>use_md5_hash(); # use_sha1_hash is the default
$signature = $rsa_priv>sign($plaintext);
print "Signed correctly\n" if ($rsa>verify($plaintext, $signature));
DESCRIPTION
Crypt::OpenSSL::RSA provides the ability to RSA encrypt strings which are somewhat shorter
than the block size of a key. It also allows for decryption, signatures and signature
verification.
NOTE: Many of the methods in this package can croak, so use eval, or Error.pm's try/catch
mechanism to capture errors. Also, while some methods from earlier versions of this
package return true on success, this (never documented) behavior is no longer the case.
Class Methods
new_public_key
Create a new Crypt::OpenSSL::RSA object by loading a public key in from a string
containing Base64/DERencoding of either the PKCS1 or X.509 representation of the key.
The string should include the BEGIN... and END... lines.
The padding is set to PKCS1_OAEP, but can be changed with the use_xxx_padding methods
new_private_key
Create a new Crypt::OpenSSL::RSA object by loading a private key in from an string
containing the Base64/DER encoding of the PKCS1 representation of the key. The string
should include the BEGIN... and END... lines. The padding is set
to PKCS1_OAEP, but can be changed with use_xxx_padding.
generate_key
Create a new Crypt::OpenSSL::RSA object by constructing a private/public key pair.
The first (mandetory) argument is the key size, while the second optional argument
specifies the public exponent (the default public exponent is 65537). The padding is
set to PKCS1_OAEP, but can be changed with use_xxx_padding methods.
new_key_from_parameters
Given Crypt::OpenSSL::Bignum objects for n, e, and optionally d, p, and q, where p and
q are the prime factors of n, e is the public exponent and d is the private exponent,
create a new Crypt::OpenSSL::RSA object using these values. If p and q are provided
and d is undef, d is computed. Note that while p and q are not necessary for a
private key, their presence will speed up computation.
import_random_seed
Import a random seed from Crypt::OpenSSL::Random, since the OpenSSL libraries won't
allow sharing of random structures across perl XS modules.
Instance Methods
DESTROY
Clean up after ourselves. In particular, erase and free the memory occupied by the
RSA key structure.
get_public_key_string
Return the Base64/DERencoded PKCS1 representation of the public key. This string has
header and footer lines:
BEGIN RSA PUBLIC KEY
END RSA PUBLIC KEY
get_public_key_x509_string
Return the Base64/DERencoded representation of the "subject public key", suitable for
use in X509 certificates. This string has header and footer lines:
BEGIN PUBLIC KEY
END PUBLIC KEY
and is the format that is produced by running "openssl rsa pubout".
get_private_key_string
Return the DERencoded PKCS1 representation of the private key.
encrypt
Encrypt a binary "string" using the public (portion of the) key.
decrypt
Decrypt a binary "string". Croaks if the key is public only.
private_encrypt
Encrypt a binary "string" using the private key. Croaks if the key is public only.
public_decrypt
Decrypt a binary "string" using the public (portion of the) key.
sign
Sign a string using the secret (portion of the) key.
verify
Check the signature on a text.
use_no_padding
Use raw RSA encryption. This mode should only be used to implement cryptographically
sound padding modes in the application code. Encrypting user data directly with RSA
is insecure.
use_pkcs1_padding
Use PKCS #1 v1.5 padding. This currently is the most widely used mode of padding.
use_pkcs1_oaep_padding
Use EMEOAEP padding as defined in PKCS #1 v2.0 with SHA1, MGF1 and an empty encoding
parameter. This mode of padding is recommended for all new applications. It is the
default mode used by Crypt::OpenSSL::RSA.
use_sslv23_padding
Use PKCS #1 v1.5 padding with an SSLspecific modification that denotes that the
server is SSL3 capable.
use_md5_hash
Use the RFC 1321 MD5 hashing algorithm by Ron Rivest when signing and verifying
messages.
use_sha1_hash
Use the RFC 3174 Secure Hashing Algorithm (FIPS 1801) when signing and verifying
messages. This is the default.
use_sha224_hash, use_sha256_hash, use_sha384_hash, use_sha512_hash
These FIPS 1802 hash algorithms, for use when signing and verifying messages, are
only available with newer openssl versions (>= 0.9.8).
use_ripemd160_hash
Dobbertin, Bosselaers and Preneel's RIPEMD hashing algorithm when signing and
verifying messages.
size
Returns the size, in bytes, of the key. All encrypted text will be of this size, and
depending on the padding mode used, the length of the text to be encrypted should be:
pkcs1_oaep_padding
at most 42 bytes less than this size.
pkcs1_padding or sslv23_padding
at most 11 bytes less than this size.
no_padding
exactly this size.
check_key
This function validates the RSA key, returning a true value if the key is valid, and a
false value otherwise. Croaks if the key is public only.
get_key_parameters
Return Crypt::OpenSSL::Bignum objects representing the values of n, e, d, p, q, d mod
(p1), d mod (q1), and 1/q mod p, where p and q are the prime factors of n, e is the
public exponent and d is the private exponent. Some of these values may return as
undef; only n and e will be defined for a public key. The Crypt::OpenSSL::Bignum
module must be installed for this to work.
is_private
Return true if this is a private key, and false if it is private only.
BUGS
There is a small memory leak when generating new keys of more than 512 bits.
AUTHOR
Ian Robertson, iroberts@cpan.org. For support, please email
perlopensslusers@lists.sourceforge.net.
SEE ALSO
perl(1), Crypt::OpenSSL::Random(3), Crypt::OpenSSL::Bignum(3), rsa(3), RSA_new(3),
RSA_public_encrypt(3), RSA_size(3), RSA_generate_key(3), RSA_check_key(3)
perl v5.16.3 20110824 RSA(3) 
