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RAND_bytes(3)
NAME
RAND_bytes, RAND_pseudo_bytes - generate random data
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 randomness to
ensure an unpredictable byte sequence.
RAND_pseudo_bytes() puts num pseudo-random bytes into buf. Pseudo-random 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 purposes in cryptographic
protocols, but usually not for key generation etc.
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 functions return -1 if they are
not supported by the current RAND method.
SEE ALSO
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.
