1.\" $OpenBSD: moduli.5,v 1.3 2001/06/24 18:50:52 provos 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.\" $FreeBSD$ 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.Nm 42file contains the system-wide Diffie-Hellman prime moduli for the 43.Xr photurisd 8 44and 45.Xr sshd 8 46programs. 47.Pp 48Each line in this file contains the following fields: 49.Va Time , Type , Tests , Tries , Size , Generator , 50and 51.Va Modulus . 52The fields are separated by white space (tab or blank). 53.Bl -tag -width indent 54.It Va Time Pq Vt yyyymmddhhmmss 55Specifies the system time that the line was appended to the file. 56The value 00000000000000 means unknown (historic). 57.\"The file is sorted in ascending order. 58.It Va Type Pq Vt decimal 59Specifies the internal structure of the prime modulus. 60.Pp 61.Bl -tag -width indent -compact 62.It 0 63unknown; 64often learned from peer during protocol operation, 65and saved for later analysis. 66.It 1 67unstructured; 68a common large number. 69.It 2 70safe (p = 2q + 1); 71meets basic structural requirements. 72.It 3 73Schnorr. 74.It 4 75Sophie-Germaine (q = (p-1)/2); 76usually generated in the process of testing safe or strong primes. 77.It 5 78strong; 79useful for RSA public key generation. 80.El 81.It Xo 82.Va Tests Pq Vt decimal 83(bit field) 84.Xc 85Specifies the methods used in checking for primality. 86Usually, more than one test is used. 87.Pp 88.Bl -tag -width indent -compact 89.It 0 90not tested; 91often learned from peer during protocol operation, 92and saved for later analysis. 93.It 1 94composite; 95failed one or more tests. 96In this case, the highest bit specifies the test that failed. 97.It 2 98sieve; 99checked for division by a range of smaller primes. 100.It 4 101Miller-Rabin. 102.It 8 103Jacobi. 104.It 16 105Elliptic Curve. 106.El 107.It Va Tries Pq Vt decimal 108Depends on the value of the highest valid Test bit, 109where the method specified is: 110.Pp 111.Bl -tag -width indent -compact 112.It 0 113not tested 114(always zero). 115.It 1 116composite 117(irrelevant). 118.It 2 119sieve; 120number of primes sieved. 121Commonly on the order of 32,000,000. 122.It 4 123Miller-Rabin; 124number of M-R iterations. 125Commonly on the order of 32 to 64. 126.It 8 127Jacobi; 128unknown 129(always zero). 130.It 16 131Elliptic Curve; 132unused 133(always zero). 134.El 135.It Va Size Pq Vt decimal 136Specifies the number of significant bits. 137.It Va Generator Pq Vt "hex string" 138Specifies the best generator for a Diffie-Hellman exchange. 1390 = unknown or variable, 1402, 3, 5, etc. 141.It Va Modulus Pq Vt "hex string" 142The prime modulus. 143.El 144.Pp 145The file is searched for moduli that meet the appropriate 146.Va Time , Size 147and 148.Va Generator 149criteria. 150When more than one meet the criteria, 151the selection should be weighted toward newer moduli, 152without completely disqualifying older moduli. 153.Sh FILES 154.Bl -tag -width ".Pa /etc/ssh/moduli" -compact 155.It Pa /etc/ssh/moduli 156.El 157.Sh SEE ALSO 158.Xr photurisd 8 , 159.Xr sshd 8 160