1.\" $OpenBSD: RAND_bytes.3,v 1.6 2018/03/27 17:35:50 schwarze Exp $ 2.\" OpenSSL b97fdb57 Nov 11 09:33:09 2016 +0100 3.\" 4.\" This file was written by Ulf Moeller <ulf@openssl.org>. 5.\" Copyright (c) 2000 The OpenSSL Project. All rights reserved. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in 16.\" the documentation and/or other materials provided with the 17.\" distribution. 18.\" 19.\" 3. All advertising materials mentioning features or use of this 20.\" software must display the following acknowledgment: 21.\" "This product includes software developed by the OpenSSL Project 22.\" for use in the OpenSSL Toolkit. (http://www.openssl.org/)" 23.\" 24.\" 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to 25.\" endorse or promote products derived from this software without 26.\" prior written permission. For written permission, please contact 27.\" openssl-core@openssl.org. 28.\" 29.\" 5. Products derived from this software may not be called "OpenSSL" 30.\" nor may "OpenSSL" appear in their names without prior written 31.\" permission of the OpenSSL Project. 32.\" 33.\" 6. Redistributions of any form whatsoever must retain the following 34.\" acknowledgment: 35.\" "This product includes software developed by the OpenSSL Project 36.\" for use in the OpenSSL Toolkit (http://www.openssl.org/)" 37.\" 38.\" THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY 39.\" EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 40.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 41.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR 42.\" ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 43.\" SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 44.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 45.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 46.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 47.\" STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 48.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 49.\" OF THE POSSIBILITY OF SUCH DAMAGE. 50.\" 51.Dd $Mdocdate: March 27 2018 $ 52.Dt RAND_BYTES 3 53.Os 54.Sh NAME 55.Nm RAND_bytes , 56.Nm RAND_pseudo_bytes 57.Nd generate random data 58.Sh SYNOPSIS 59.In openssl/rand.h 60.Ft int 61.Fo RAND_bytes 62.Fa "unsigned char *buf" 63.Fa "int num" 64.Fc 65.Ft int 66.Fo RAND_pseudo_bytes 67.Fa "unsigned char *buf" 68.Fa "int num" 69.Fc 70.Sh DESCRIPTION 71These functions are deprecated and only retained for compatibility 72with legacy application programs. 73Use 74.Xr arc4random_buf 3 75instead. 76.Pp 77.Fn RAND_bytes 78puts 79.Fa num 80cryptographically strong pseudo-random bytes into 81.Fa buf . 82.Pp 83.Fn RAND_pseudo_bytes 84puts 85.Fa num 86pseudo-random bytes into 87.Fa buf . 88Pseudo-random byte sequences generated by 89.Fn RAND_pseudo_bytes 90will be unique if they are of sufficient length, but are not necessarily 91unpredictable. 92They can be used for non-cryptographic purposes and for certain purposes 93in cryptographic protocols, but usually not for key generation etc. 94.Sh RETURN VALUES 95.Fn RAND_bytes 96returns 1. 97.Fn RAND_pseudo_bytes 98returns 1. 99.Sh HISTORY 100.Fn RAND_bytes 101first appeared in SSLeay 0.5.1 and has been available since 102.Ox 2.4 . 103It has a return value since OpenSSL 0.9.5 and 104.Ox 2.7 . 105.Pp 106.Fn RAND_pseudo_bytes 107first appeared in OpenSSL 0.9.5 and has been available since 108.Ox 2.7 . 109