1.\" $OpenBSD: moduli.5,v 1.8 2003/07/04 08:03:13 markus Exp $ 2.\" 3.\" Copyright 1997, 2000 William Allen Simpson <wsimpson@greendragon.com> 4.\" All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software designed by William Allen Simpson. 17.\" 4. The name of the author may not be used to endorse or promote products 18.\" derived from this software without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 21.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 22.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 23.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 24.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 25.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 26.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 27.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 28.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 29.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 30.\" 31.\" Manual page, using -mandoc macros 32.\" 33.Dd July 28, 1997 34.Dt MODULI 5 35.Os 36.Sh NAME 37.Nm moduli 38.Nd system moduli file 39.Sh DESCRIPTION 40The 41.Pa /etc/moduli 42file contains the system-wide Diffie-Hellman prime moduli for 43.Xr sshd 8 . 44.Pp 45Each line in this file contains the following fields: 46Time, Type, Tests, Tries, Size, Generator, Modulus. 47The fields are separated by white space (tab or blank). 48.Pp 49.Fa Time : yyyymmddhhmmss . 50Specifies the system time that the line was appended to the file. 51The value 00000000000000 means unknown (historic). 52.\"The file is sorted in ascending order. 53.Pp 54.Fa Type : decimal . 55Specifies the internal structure of the prime modulus. 56.Pp 57.Bl -tag -width indent -offset indent -compact 58.It 0 : 59unknown; 60often learned from peer during protocol operation, 61and saved for later analysis. 62.It 1 : 63unstructured; 64a common large number. 65.It 2 : 66safe (p = 2q + 1); 67meets basic structural requirements. 68.It 3 : 69Schnorr. 70.It 4 : 71Sophie-Germaine (q = (p-1)/2); 72usually generated in the process of testing safe or strong primes. 73.It 5 : 74strong; 75useful for RSA public key generation. 76.El 77.Pp 78.Fa Tests : decimal (bit field) . 79Specifies the methods used in checking for primality. 80Usually, more than one test is used. 81.Pp 82.Bl -tag -width indent -offset indent -compact 83.It 0 : 84not tested; 85often learned from peer during protocol operation, 86and saved for later analysis. 87.It 1 : 88composite; 89failed one or more tests. 90In this case, the highest bit specifies the test that failed. 91.It 2 : 92sieve; 93checked for division by a range of smaller primes. 94.It 4 : 95Miller-Rabin. 96.It 8 : 97Jacobi. 98.It 16 : 99Elliptic Curve. 100.El 101.Pp 102.Fa Tries : decimal . 103Depends on the value of the highest valid Test bit, 104where the method specified is: 105.Pp 106.Bl -tag -width indent -offset indent -compact 107.It 0 : 108not tested 109(always zero). 110.It 1 : 111composite 112(irrelevant). 113.It 2 : 114sieve; 115number of primes sieved. 116Commonly on the order of 32,000,000. 117.It 4 : 118Miller-Rabin; 119number of M-R iterations. 120Commonly on the order of 32 to 64. 121.It 8 : 122Jacobi; 123unknown 124(always zero). 125.It 16 : 126Elliptic Curve; 127unused 128(always zero). 129.El 130.Pp 131.Fa Size : decimal . 132Specifies the number of the most significant bit (0 to M). 133.Pp 134.Fa Generator : hex string . 135Specifies the best generator for a Diffie-Hellman exchange. 1360 = unknown or variable, 1372, 3, 5, etc. 138.Pp 139.Fa Modulus : hex string . 140The prime modulus. 141.Pp 142The file is searched for moduli that meet the appropriate 143Time, Size and Generator criteria. 144When more than one meet the criteria, 145the selection should be weighted toward newer moduli, 146without completely disqualifying older moduli. 147.Sh FILES 148.Bl -tag -width /etc/moduli -compact 149.It Pa /etc/moduli 150.El 151.Sh SEE ALSO 152.Xr sshd 8 153