2fe8fb192f
There is important information about booting non-ack images in docs/UPDATING. ack/aout-format images can't be built any more, and booting clang/ELF-format ones is a little different. Updating to the new boot monitor is recommended. Changes in this commit: . drop boot monitor -> allowing dropping ack support . facility to copy ELF boot files to /boot so that old boot monitor can still boot fairly easily, see UPDATING . no more ack-format libraries -> single-case libraries . some cleanup of OBJECT_FMT, COMPILER_TYPE, etc cases . drop several ack toolchain commands, but not all support commands (e.g. aal is gone but acksize is not yet). . a few libc files moved to netbsd libc dir . new /bin/date as minix date used code in libc/ . test compile fix . harmonize includes . /usr/lib is no longer special: without ack, /usr/lib plays no kind of special bootstrapping role any more and bootstrapping is done exclusively through packages, so releases depend even less on the state of the machine making them now. . rename nbsd_lib* to lib* . reduce mtree
113 lines
3.8 KiB
Groff
113 lines
3.8 KiB
Groff
.\" $NetBSD: arc4random.3,v 1.7 2005/12/26 19:40:14 perry Exp $
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.\" $OpenBSD: arc4random.3,v 1.17 2000/12/21 14:07:41 aaron Exp $
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.\"
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.\" Copyright 1997 Niels Provos <provos@physnet.uni-hamburg.de>
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by Niels Provos.
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.\" 4. The name of the author may not be used to endorse or promote products
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.\" derived from this software without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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.\"
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.\" Manual page, using -mandoc macros
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.\"
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.Dd April 15, 1997
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.Dt ARC4RANDOM 3
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.Os
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.Sh NAME
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.Nm arc4random ,
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.Nm arc4random_stir ,
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.Nm arc4random_addrandom
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.Nd arc4 random number generator
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In stdlib.h
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.Ft uint32_t
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.Fn arc4random "void"
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.Ft void
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.Fn arc4random_stir "void"
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.Ft void
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.Fn arc4random_addrandom "u_char *dat" "int datlen"
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.Sh DESCRIPTION
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The
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.Fn arc4random
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function provides a high quality 32-bit pseudo-random
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number very quickly.
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.Fn arc4random
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seeds itself on a regular basis from the kernel strong random number
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subsystem described in
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.Xr rnd 4 .
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On each call, an ARC4 generator is used to generate a new result.
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The
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.Fn arc4random
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function uses the ARC4 cipher key stream generator,
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which uses 8*8 8 bit S-Boxes.
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The S-Boxes can be in about (2**1700) states.
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.Pp
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.Fn arc4random
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fits into a middle ground not covered by other subsystems such as
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the strong, slow, and resource expensive random
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devices described in
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.Xr rnd 4
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versus the fast but poor quality interfaces described in
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.Xr rand 3 ,
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.Xr random 3 ,
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and
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.Xr drand48 3 .
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.Pp
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The
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.Fn arc4random_stir
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function reads data from
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.Pa /dev/urandom
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and uses it to permute the S-Boxes via
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.Fn arc4random_addrandom .
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.Pp
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There is no need to call
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.Fn arc4random_stir
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before using
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.Fn arc4random ,
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since
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.Fn arc4random
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automatically initializes itself.
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.Sh SEE ALSO
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.Xr rand 3 ,
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.Xr rand48 3 ,
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.Xr random 3
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.Sh HISTORY
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An algorithm called
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.Pa RC4
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was designed by RSA Data Security, Inc.
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It was considered a trade secret, but not trademarked.
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Because it was a trade secret, it obviously could not be patented.
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A clone of this was posted anonymously to USENET and confirmed to
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be equivalent by several sources who had access to the original cipher.
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Because of the trade secret situation, RSA Data Security, Inc. can do
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nothing about the release of the ARC4 algorithm.
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Since
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.Pa RC4
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used to be a trade secret, the cipher is now referred to as
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.Pa ARC4 .
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.Pp
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These functions first appeared in
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.Ox 2.1 .
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