NAME

       RAND_bytes, RAND_priv_bytes, RAND_pseudo_bytes - generate random data

SYNOPSIS

        #include <openssl/rand.h>

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

       Deprecated:

        #if OPENSSL_API_COMPAT < 0x10100000L
        int RAND_pseudo_bytes(unsigned char *buf, int num);
        #endif

DESCRIPTION

       RAND_bytes() puts num cryptographically strong pseudo-random bytes into buf.

       RAND_priv_bytes() has the same semantics as RAND_bytes().  It is intended to be used for
       generating values that should remain private. If using the default RAND_METHOD, this
       function uses a separate "private" PRNG instance so that a compromise of the "public" PRNG
       instance will not affect the secrecy of these private values, as described in RAND(7) and
       RAND_DRBG(7).

NOTES

       Always check the error return value of RAND_bytes() and RAND_priv_bytes() and do not take
       randomness for granted: an error occurs if the CSPRNG has not been seeded with enough
       randomness to ensure an unpredictable byte sequence.

RETURN VALUES

       RAND_bytes() and RAND_priv_bytes() return 1 on success, -1 if not supported by the current
       RAND method, or 0 on other failure. The error code can be obtained by ERR_get_error(3).

HISTORY

       • RAND_pseudo_bytes() was deprecated in OpenSSL 1.1.0; use RAND_bytes() instead.

       • RAND_priv_bytes() was added in OpenSSL 1.1.1.

SEE ALSO

       RAND_add(3), RAND_bytes(3), RAND_priv_bytes(3), ERR_get_error(3), RAND(7), RAND_DRBG(7)

COPYRIGHT

       Copyright 2000-2018 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the OpenSSL license (the "License").  You may not use this file except in
       compliance with the License.  You can obtain a copy in the file LICENSE in the source
       distribution or at <https://www.openssl.org/source/license.html>.