RAND_bytes(3) - NetBSD Manual Pages

Command: Section: Arch: Collection:  
RAND_bytes(3)                       OpenSSL                      RAND_bytes(3)




NAME
RAND_bytes, RAND_pseudo_bytes - generate random data
LIBRARY
libcrypto, -lcrypto
SYNOPSIS
#include <openssl/rand.h> int RAND_bytes(unsigned char *buf, int num); int RAND_pseudo_bytes(unsigned char *buf, int num);
DESCRIPTION
RAND_bytes() puts num cryptographically strong pseudo-random bytes into buf. An error occurs if the PRNG has not been seeded with enough ran- domness to ensure an unpredictable byte sequence. RAND_pseudo_bytes() puts num pseudo-random bytes into buf. Pseudo-ran- dom byte sequences generated by RAND_pseudo_bytes() will be unique if they are of sufficient length, but are not necessarily unpredictable. They can be used for non-cryptographic purposes and for certain pur- poses in cryptographic protocols, but usually not for key generation etc. The contents of buf is mixed into the entropy pool before retrieving the new pseudo-random bytes unless disabled at compile time (see FAQ).
RETURN VALUES
RAND_bytes() returns 1 on success, 0 otherwise. The error code can be obtained by ERR_get_error(3). RAND_pseudo_bytes() returns 1 if the bytes generated are cryptographically strong, 0 otherwise. Both func- tions return -1 if they are not supported by the current RAND method.
SEE ALSO
openssl_rand(3), ERR_get_error(3), RAND_add(3)
HISTORY
RAND_bytes() is available in all versions of SSLeay and OpenSSL. It has a return value since OpenSSL 0.9.5. RAND_pseudo_bytes() was added in OpenSSL 0.9.5. 0.9.9-dev 2008-05-09 RAND_bytes(3)
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