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.
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 functions return -1 if
they are not supported by the current RAND method.
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.
