RAND_bytes(3)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
The RAND_bytes() function puts num cryptographically strong pseudo-ran‐
dom bytes into buf. An error occurs if the PRNG has not been seeded
with enough randomness to ensure an unpredictable byte sequence.
The RAND_pseudo_bytes() function puts num pseudo-random bytes into buf.
Pseudo-random byte sequences generated by the RAND_pseudo_bytes() func‐
tion will be unique if they are of sufficient length, but are not nec‐
essarily unpredictable. They can be used for non-cryptographic pur‐
poses and for certain purposes in cryptographic protocols, but usually
not for key generation etc.
RETURN VALUES
The RAND_bytes() functon returns 1 on success, 0 otherwise. The error
code can be obtained by using ERR_get_error(). The RAND_pseudo_bytes()
function 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.
HISTORY
The RAND_bytes() function is available in all versions of SSLeay and
OpenSSL. It has a return value since OpenSSL 0.9.5. The
RAND_pseudo_bytes() function was added in OpenSSL 0.9.5.
SEE ALSO
Functions: rand_ssl(3), err(3), RAND_add(3)RAND_bytes(3)
