randomid_new(3) [netbsd man page]

RANDOMID(3)						   BSD Library Functions Manual 					       RANDOMID(3)

NAME

     randomid randomid_new, randomid_delete, -- provide pseudo-random data stream without repetitions

SYNOPSIS

     #include <sys/types.h>
     #include <randomid.h>

     uint32_t
     randomid(randomid_t ctx);

     randomid_t
     randomid_new(int bits, long timeo);

     void
     randomid_delete(randomid_t ctx);

DESCRIPTION

     The randomid() function provides pseudo-random data stream, which is guaranteed not to generate the same number twice during a certain dura-
     tion.  ctx is the context which holds internal state for the random number generator.

     To initialize a context, randomid_new is used.  bits specifies the bitwidth of the value generated by randomid().	Currently 32, 20, and 16
     are supported.  timeo specifies the reinitialization interval in seconds.	timeo has to be bigger than RANDOMID_TIMEO_MIN.  randomid_new
     returns a dynamically-allocated memory region allocated by malloc(3).

     randomid_delete() will free(3) the internal state ctx.

     The same number may appear after two reinitialization events of the internal state, ctx.  Reinitialization happens when the random number
     generator cycle is exhausted, or timeo seconds have passed since the last reinitialization.  For instance, ctx configured to generate 16 bit
     data stream will reinitialize its internal state every 30000 calls to randomid() (or after timeo seconds), therefore the same data will not
     appear until after 30000 calls to randomid() (or after timeo seconds).

     The internal state, ctx, determines the data stream generated by randomid().  ctx must be allocated per data stream (such as a specific data
     field).  It must not be shared among multiple data streams with different usage.

EXAMPLES

	   #include <stdio.h>
	   #include <sys/types.h>
	   #include <randomid.h>

	   uint32_t
	   genid(void)
	   {
		   static randomid_t ctx = NULL;

		   if (!ctx)
			   ctx = randomid_new(16, (long)3600);
		   return randomid(ctx);
	   }

ERRORS

     randomid_new() returns NULL on error and sets the external variable errno.

SEE ALSO

     arc4random(3)

HISTORY

     The pseudo-random data stream generator was designed by Niels Provos for OpenBSD IPv4 fragment ID generation.  randomid() is a generalized
     version of the generator, reworked by Jun-ichiro itojun Hagino, and was introduced in NetBSD 2.0.

BSD
								  January 5, 2006							       BSD

EVP_SignInit(3) 						      OpenSSL							   EVP_SignInit(3)

NAME

       EVP_SignInit, EVP_SignUpdate, EVP_SignFinal - EVP signing functions

SYNOPSIS

	#include <openssl/evp.h>

	int EVP_SignInit_ex(EVP_MD_CTX *ctx, const EVP_MD *type, ENGINE *impl);
	int EVP_SignUpdate(EVP_MD_CTX *ctx, const void *d, unsigned int cnt);
	int EVP_SignFinal(EVP_MD_CTX *ctx,unsigned char *sig,unsigned int *s, EVP_PKEY *pkey);

	void EVP_SignInit(EVP_MD_CTX *ctx, const EVP_MD *type);

	int EVP_PKEY_size(EVP_PKEY *pkey);

DESCRIPTION

       The EVP signature routines are a high level interface to digital signatures.

       EVP_SignInit_ex() sets up signing context ctx to use digest type from ENGINE impl. ctx must be initialized with EVP_MD_CTX_init() before
       calling this function.

       EVP_SignUpdate() hashes cnt bytes of data at d into the signature context ctx. This function can be called several times on the same ctx to
       include additional data.

       EVP_SignFinal() signs the data in ctx using the private key pkey and places the signature in sig. If the s parameter is not NULL then the
       number of bytes of data written (i.e. the length of the signature) will be written to the integer at s, at most EVP_PKEY_size(pkey) bytes
       will be written.

       EVP_SignInit() initializes a signing context ctx to use the default implementation of digest type.

       EVP_PKEY_size() returns the maximum size of a signature in bytes. The actual signature returned by EVP_SignFinal() may be smaller.

RETURN VALUES

       EVP_SignInit_ex(), EVP_SignUpdate() and EVP_SignFinal() return 1 for success and 0 for failure.

       EVP_PKEY_size() returns the maximum size of a signature in bytes.

       The error codes can be obtained by ERR_get_error(3).

NOTES

       The EVP interface to digital signatures should almost always be used in preference to the low level interfaces. This is because the code
       then becomes transparent to the algorithm used and much more flexible.

       Due to the link between message digests and public key algorithms the correct digest algorithm must be used with the correct public key
       type. A list of algorithms and associated public key algorithms appears in EVP_DigestInit(3).

       When signing with DSA private keys the random number generator must be seeded or the operation will fail. The random number generator does
       not need to be seeded for RSA signatures.

       The call to EVP_SignFinal() internally finalizes a copy of the digest context.  This means that calls to EVP_SignUpdate() and EVP_SignFi-
       nal() can be called later to digest and sign additional data.

       Since only a copy of the digest context is ever finalized the context must be cleaned up after use by calling EVP_MD_CTX_cleanup() or a
       memory leak will occur.

BUGS

       Older versions of this documentation wrongly stated that calls to EVP_SignUpdate() could not be made after calling EVP_SignFinal().

SEE ALSO

       EVP_VerifyInit(3), EVP_DigestInit(3), err(3), evp(3), hmac(3), md2(3), md5(3), mdc2(3), ripemd(3), sha(3), dgst(1)

HISTORY

       EVP_SignInit(), EVP_SignUpdate() and EVP_SignFinal() are available in all versions of SSLeay and OpenSSL.

       EVP_SignInit_ex() was added in OpenSSL 0.9.7.

0.9.7a								    2002-07-18							   EVP_SignInit(3)