From d6f8248cc33263cd78b9cad33e80e4ed8643fb6b Mon Sep 17 00:00:00 2001 From: "Peter S. Mazinger" Date: Sat, 14 May 2011 03:29:53 +0200 Subject: update arc4random from bug #885 Add config option to provide arc4random without device access. Signed-off-by: Peter S. Mazinger Signed-off-by: Bernhard Reutner-Fischer --- docs/man/arc4random.3 | 110 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 110 insertions(+) create mode 100644 docs/man/arc4random.3 (limited to 'docs') diff --git a/docs/man/arc4random.3 b/docs/man/arc4random.3 new file mode 100644 index 000000000..933d2eb0c --- /dev/null +++ b/docs/man/arc4random.3 @@ -0,0 +1,110 @@ +.\" $OpenBSD: arc4random.3,v 1.19 2005/07/17 08:50:55 jaredy Exp $ +.\" +.\" Copyright 1997 Niels Provos +.\" All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" 3. All advertising materials mentioning features or use of this software +.\" must display the following acknowledgement: +.\" This product includes software developed by Niels Provos. +.\" 4. The name of the author may not be used to endorse or promote products +.\" derived from this software without specific prior written permission. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR +.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES +.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. +.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, +.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT +.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF +.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +.\" +.\" Manual page, using -mandoc macros +.\" +.Dd April 15, 1997 +.Dt ARC4RANDOM 3 +.Os +.Sh NAME +.Nm arc4random , +.Nm arc4random_stir , +.Nm arc4random_addrandom +.Nd arc4 random number generator +.Sh SYNOPSIS +.Fd #include +.Ft uint32_t +.Fn arc4random "void" +.Ft void +.Fn arc4random_stir "void" +.Ft void +.Fn arc4random_addrandom "u_char *dat" "int datlen" +.Sh DESCRIPTION +The +.Fn arc4random +function provides a high quality 32-bit pseudo-random +number very quickly. +.Fn arc4random +seeds itself on a regular basis from the kernel strong random number +subsystem described in +.Xr random 4 . +On each call, an ARC4 generator is used to generate a new result. +The +.Fn arc4random +function uses the ARC4 cipher key stream generator, +which uses 8*8 8-bit S-Boxes. +The S-Boxes can be in about (2**1700) states. +.Pp +.Fn arc4random +fits into a middle ground not covered by other subsystems such as +the strong, slow, and resource expensive random +devices described in +.Xr random 4 +versus the fast but poor quality interfaces described in +.Xr rand 3 , +.Xr random 3 , +and +.Xr drand48 3 . +.Pp +The +.Fn arc4random_stir +function reads data from a pseudo-random device, usually +.Pa /dev/urandom, +and uses it to permute the S-Boxes via +.Fn arc4random_addrandom . +.Pp +There is no need to call +.Fn arc4random_stir +before using +.Fn arc4random , +since +.Fn arc4random +automatically initializes itself. +.Sh SEE ALSO +.Xr rand 3 , +.Xr rand48 3 , +.Xr random 3 +.Sh HISTORY +An algorithm called +.Pa RC4 +was designed by RSA Data Security, Inc. +It was considered a trade secret. +Because it was a trade secret, it obviously could not be patented. +A clone of this was posted anonymously to USENET and confirmed to +be equivalent by several sources who had access to the original cipher. +Because of the trade secret situation, RSA Data Security, Inc. can do +nothing about the release of the ARC4 algorithm. +Since +.Pa RC4 +used to be a trade secret, the cipher is now referred to as +.Pa ARC4 . +.Pp +These functions first appeared in +.Ox 2.1 . -- cgit v1.2.3