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RAND_bytes(3)                       OpenSSL                      RAND_bytes(3)




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).


SEE ALSO

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


HISTORY

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

       o The RAND_priv_bytes() function was added in OpenSSL 1.1.1.


COPYRIGHT

       Copyright 2000-2019 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>.



1.1.1c                            2019-05-28                     RAND_bytes(3)

openssl 1.1.1c - Generated Tue Jun 11 11:06:36 CDT 2019
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