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
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.
