NAME    [Toc]    [Back]

       RAND_bytes, RAND_pseudo_bytes - generate random data

LIBRARY    [Toc]    [Back]

       libcrypto, -lcrypto

SYNOPSIS    [Toc]    [Back]

        #include <openssl/rand.h>

        int RAND_bytes(unsigned char *buf, int num);

        int RAND_pseudo_bytes(unsigned char *buf, int num);

DESCRIPTION    [Toc]    [Back]

       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    [Toc]    [Back]

       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    [Toc]    [Back]

       openssl_rand(3), openssl_err(3), RAND_add(3)

HISTORY    [Toc]    [Back]

       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.



2000-07-22                    0.9.6g                RAND_bytes(3)