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.\" $OpenBSD: moduli.5,v 1.7 2003/03/06 20:48:35 jmc Exp $
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.\" Copyright 1997, 2000 William Allen Simpson <wsimpson@greendragon.com>
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.\" All rights reserved.
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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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.\" 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 designed by William Allen Simpson.
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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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.\" 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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.\" Manual page, using -mandoc macros
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.Nd system moduli file
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file contains the system-wide Diffie-Hellman prime moduli for
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Each line in this file contains the following fields:
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Time, Type, Tests, Tries, Size, Generator, Modulus.
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The fields are separated by white space (tab or blank).
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.Fa Time : yyyymmddhhmmss .
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Specifies the system time that the line was appended to the file.
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The value 00000000000000 means unknown (historic).
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.\"The file is sorted in ascending order.
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Specifies the internal structure of the prime modulus.
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.Bl -tag -width indent -offset indent -compact
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often learned from peer during protocol operation,
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and saved for later analysis.
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a common large number.
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meets basic structural requirements.
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Sophie-Germaine (q = (p-1)/2);
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usually generated in the process of testing safe or strong primes.
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useful for RSA public key generation.
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.Fa Tests : decimal (bit field) .
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Specifies the methods used in checking for primality.
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Usually, more than one test is used.
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.Bl -tag -width indent -offset indent -compact
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often learned from peer during protocol operation,
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and saved for later analysis.
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failed one or more tests.
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In this case, the highest bit specifies the test that failed.
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checked for division by a range of smaller primes.
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.Fa Tries : decimal .
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Depends on the value of the highest valid Test bit,
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where the method specified is:
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.Bl -tag -width indent -offset indent -compact
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number of primes sieved.
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Commonly on the order of 32,000,000.
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number of M-R iterations.
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Commonly on the order of 32 to 64.
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Specifies the number of significant bits.
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.Fa Generator : hex string .
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Specifies the best generator for a Diffie-Hellman exchange.
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0 = unknown or variable,
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.Fa Modulus : hex string .
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The file is searched for moduli that meet the appropriate
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Time, Size and Generator criteria.
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When more than one meet the criteria,
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the selection should be weighted toward newer moduli,
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without completely disqualifying older moduli.
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.Bl -tag -width /etc/ssh/moduli -compact
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.It Pa /etc/ssh/moduli