1=pod 2 3=head1 NAME 4 5RAND_bytes, RAND_priv_bytes, RAND_pseudo_bytes - generate random data 6 7=head1 SYNOPSIS 8 9 #include <openssl/rand.h> 10 11 int RAND_bytes(unsigned char *buf, int num); 12 int RAND_priv_bytes(unsigned char *buf, int num); 13 14Deprecated: 15 16 #if OPENSSL_API_COMPAT < 0x10100000L 17 int RAND_pseudo_bytes(unsigned char *buf, int num); 18 #endif 19 20=head1 DESCRIPTION 21 22RAND_bytes() puts B<num> cryptographically strong pseudo-random bytes 23into B<buf>. 24 25RAND_priv_bytes() has the same semantics as RAND_bytes(). It is intended to 26be used for generating values that should remain private. If using the 27default RAND_METHOD, this function uses a separate "private" PRNG 28instance so that a compromise of the "public" PRNG instance will not 29affect the secrecy of these private values, as described in L<RAND(7)> 30and L<RAND_DRBG(7)>. 31 32=head1 NOTES 33 34Always check the error return value of RAND_bytes() and 35RAND_priv_bytes() and do not take randomness for granted: an error occurs 36if the CSPRNG has not been seeded with enough randomness to ensure an 37unpredictable byte sequence. 38 39=head1 RETURN VALUES 40 41RAND_bytes() and RAND_priv_bytes() 42return 1 on success, -1 if not supported by the current 43RAND method, or 0 on other failure. The error code can be 44obtained by L<ERR_get_error(3)>. 45 46=head1 HISTORY 47 48=over 2 49 50=item * 51 52RAND_pseudo_bytes() was deprecated in OpenSSL 1.1.0; use RAND_bytes() instead. 53 54=item * 55 56RAND_priv_bytes() was added in OpenSSL 1.1.1. 57 58=back 59 60=head1 SEE ALSO 61 62L<RAND_add(3)>, 63L<RAND_bytes(3)>, 64L<RAND_priv_bytes(3)>, 65L<ERR_get_error(3)>, 66L<RAND(7)>, 67L<RAND_DRBG(7)> 68 69=head1 COPYRIGHT 70 71Copyright 2000-2018 The OpenSSL Project Authors. All Rights Reserved. 72 73Licensed under the OpenSSL license (the "License"). You may not use 74this file except in compliance with the License. You can obtain a copy 75in the file LICENSE in the source distribution or at 76L<https://www.openssl.org/source/license.html>. 77 78=cut 79