1e9a56ad5SMark Murray.\" FreeSec: libcrypt for NetBSD 2e9a56ad5SMark Murray.\" 3e9a56ad5SMark Murray.\" Copyright (c) 1994 David Burren 4e9a56ad5SMark Murray.\" All rights reserved. 5e9a56ad5SMark Murray.\" 6e9a56ad5SMark Murray.\" Redistribution and use in source and binary forms, with or without 7e9a56ad5SMark Murray.\" modification, are permitted provided that the following conditions 8e9a56ad5SMark Murray.\" are met: 9e9a56ad5SMark Murray.\" 1. Redistributions of source code must retain the above copyright 10e9a56ad5SMark Murray.\" notice, this list of conditions and the following disclaimer. 11e9a56ad5SMark Murray.\" 2. Redistributions in binary form must reproduce the above copyright 12e9a56ad5SMark Murray.\" notice, this list of conditions and the following disclaimer in the 13e9a56ad5SMark Murray.\" documentation and/or other materials provided with the distribution. 14e9a56ad5SMark Murray.\" 4. Neither the name of the author nor the names of other contributors 15e9a56ad5SMark Murray.\" may be used to endorse or promote products derived from this software 16e9a56ad5SMark Murray.\" without specific prior written permission. 17e9a56ad5SMark Murray.\" 18e9a56ad5SMark Murray.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 19e9a56ad5SMark Murray.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20e9a56ad5SMark Murray.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21e9a56ad5SMark Murray.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 22e9a56ad5SMark Murray.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23e9a56ad5SMark Murray.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24e9a56ad5SMark Murray.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25e9a56ad5SMark Murray.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26e9a56ad5SMark Murray.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27e9a56ad5SMark Murray.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28e9a56ad5SMark Murray.\" SUCH DAMAGE. 29e9a56ad5SMark Murray.\" 30e9a56ad5SMark Murray.\" $FreeBSD$ 31e9a56ad5SMark Murray.\" 32e9a56ad5SMark Murray.\" Manual page, using -mandoc macros 33e9a56ad5SMark Murray.\" 34e9a56ad5SMark Murray.Dd January 19, 1997 35e9a56ad5SMark Murray.Dt CRYPT 3 36e9a56ad5SMark Murray.Os "FreeSec 1.0" 37e9a56ad5SMark Murray.Sh NAME 38e9a56ad5SMark Murray.Nm crypt 39e9a56ad5SMark Murray.Nd Trapdoor encryption 40f45f23ddSAlexey Zelkin.Sh LIBRARY 41f45f23ddSAlexey Zelkin.Lb libcrypt 42e9a56ad5SMark Murray.Sh SYNOPSIS 43f92c744fSBruce Evans.Fd #include <unistd.h> 44d3f0d184SBruce Evans.Ft char * 45d3f0d184SBruce Evans.Fn crypt "const char *key" "const char *salt" 46e9a56ad5SMark Murray.Sh DESCRIPTION 47e9a56ad5SMark MurrayThe 48e9a56ad5SMark Murray.Fn crypt 49e9a56ad5SMark Murrayfunction performs password hashing with additional code added to 50e9a56ad5SMark Murraydeter key search attempts. Different algorithms can be used to 51e9a56ad5SMark Murrayin the hash. 52e9a56ad5SMark Murray.\" 53e9a56ad5SMark Murray.\" NOTICE: 54e9a56ad5SMark Murray.\" If you add more algorithms, make sure to update this list 55e9a56ad5SMark Murray.\" and the default used for the Traditional format, below. 56e9a56ad5SMark Murray.\" 57e9a56ad5SMark MurrayCurrently these include the 58e9a56ad5SMark Murray.Tn NBS 59f45f23ddSAlexey Zelkin.Tn Data Encryption Standard (DES) , 60f32b1300SKris Kennawayand 61f32b1300SKris Kennaway.Tn MD5 . 62f45f23ddSAlexey ZelkinThe algorithm used will depend upon the format of the Salt--following 63f45f23ddSAlexey Zelkinthe Modular Crypt Format (MCF)--and if 64f45f23ddSAlexey Zelkin.Tn DES 65f45f23ddSAlexey Zelkinis installed or not. 66e9a56ad5SMark Murray.Pp 67e9a56ad5SMark MurrayThe first argument to 68f45f23ddSAlexey Zelkin.Nm 69e9a56ad5SMark Murrayis the data to hash (usually a password), in a 70e9a56ad5SMark Murray.Dv null Ns -terminated 71e9a56ad5SMark Murraystring. 72e9a56ad5SMark MurrayThe second is the salt, in one of three forms: 73e9a56ad5SMark Murray.Pp 74e9a56ad5SMark Murray.Bl -tag -width Traditional -compact -offset indent 75e9a56ad5SMark Murray.It Extended 76f45f23ddSAlexey ZelkinIf it begins with an underscore 77f45f23ddSAlexey Zelkin.Pq Dq _ 78f45f23ddSAlexey Zelkinthen the 79f45f23ddSAlexey Zelkin.Tn DES 80f45f23ddSAlexey ZelkinExtended Format 81e9a56ad5SMark Murrayis used in interpreting both the the key and the salt, as outlined below. 82e9a56ad5SMark Murray.It Modular 83f45f23ddSAlexey ZelkinIf it begins with the string 84f45f23ddSAlexey Zelkin.Dq $digit$ 85f45f23ddSAlexey Zelkinthen the Modular Crypt Format is used, as outlined below. 86e9a56ad5SMark Murray.It Traditional 87e9a56ad5SMark MurrayIf neither of the above is true, it assumes the Traditional Format, 88e9a56ad5SMark Murrayusing the entire string as the salt (or the first portion). 89e9a56ad5SMark Murray.El 90e9a56ad5SMark Murray.Pp 91e9a56ad5SMark MurrayAll routines are designed to be time-consuming. A brief test on a 92f45f23ddSAlexey Zelkin.Tn Pentium 93f45f23ddSAlexey Zelkin166/MMX shows the 94f45f23ddSAlexey Zelkin.Tn DES 95f45f23ddSAlexey Zelkincrypt to do approximately 2640 crypts 9600587201SMark Murraya CPU second and MD5 to do about 62 crypts a CPU second. 97e9a56ad5SMark Murray.Ss DES Extended Format: 98e9a56ad5SMark Murray.Pp 99e9a56ad5SMark MurrayThe 100e9a56ad5SMark Murray.Ar key 101e9a56ad5SMark Murrayis divided into groups of 8 characters (the last group is null-padded) 102e9a56ad5SMark Murrayand the low-order 7 bits of each each character (56 bits per group) are 103f45f23ddSAlexey Zelkinused to form the 104f45f23ddSAlexey Zelkin.Tn DES 105f45f23ddSAlexey Zelkinkey as follows: 106f45f23ddSAlexey Zelkinthe first group of 56 bits becomes the initial 107f45f23ddSAlexey Zelkin.Tn DES 108f45f23ddSAlexey Zelkinkey. 109f45f23ddSAlexey ZelkinFor each additional group, the XOR of the encryption of the current 110f45f23ddSAlexey Zelkin.Tn DES 111f45f23ddSAlexey Zelkinkey with itself and the group bits becomes the next 112f45f23ddSAlexey Zelkin.Tn DES 113f45f23ddSAlexey Zelkinkey. 114e9a56ad5SMark Murray.Pp 115e9a56ad5SMark MurrayThe salt is a 9-character array consisting of an underscore followed 116e9a56ad5SMark Murrayby 4 bytes of iteration count and 4 bytes of salt. 117e9a56ad5SMark MurrayThese are encoded as printable characters, 6 bits per character, 118e9a56ad5SMark Murrayleast significant character first. 119e9a56ad5SMark MurrayThe values 0 to 63 are encoded as ``./0-9A-Za-z''. 120e9a56ad5SMark MurrayThis allows 24 bits for both 121e9a56ad5SMark Murray.Fa count 122e9a56ad5SMark Murrayand 123e9a56ad5SMark Murray.Fa salt . 124e9a56ad5SMark Murray.Pp 125e9a56ad5SMark MurrayThe 126e9a56ad5SMark Murray.Fa salt 127e9a56ad5SMark Murrayintroduces disorder in the 128e9a56ad5SMark Murray.Tn DES 129e9a56ad5SMark Murrayalgorithm in one of 16777216 or 4096 possible ways 130e9a56ad5SMark Murray(ie. with 24 or 12 bits: if bit 131e9a56ad5SMark Murray.Em i 132e9a56ad5SMark Murrayof the 133e9a56ad5SMark Murray.Ar salt 134e9a56ad5SMark Murrayis set, then bits 135e9a56ad5SMark Murray.Em i 136e9a56ad5SMark Murrayand 137e9a56ad5SMark Murray.Em i+24 138e9a56ad5SMark Murrayare swapped in the 139e9a56ad5SMark Murray.Tn DES 140e9a56ad5SMark MurrayE-box output). 141e9a56ad5SMark Murray.Pp 142f45f23ddSAlexey ZelkinThe 143f45f23ddSAlexey Zelkin.Tn DES 144f45f23ddSAlexey Zelkinkey is used to encrypt a 64-bit constant using 145e9a56ad5SMark Murray.Ar count 146e9a56ad5SMark Murrayiterations of 147e9a56ad5SMark Murray.Tn DES . 148e9a56ad5SMark MurrayThe value returned is a 149e9a56ad5SMark Murray.Dv null Ns -terminated 150e9a56ad5SMark Murraystring, 20 or 13 bytes (plus null) in length, consisting of the 151e9a56ad5SMark Murray.Ar salt 152e9a56ad5SMark Murrayfollowed by the encoded 64-bit encryption. 153e9a56ad5SMark Murray.Ss "Modular" crypt: 154e9a56ad5SMark Murray.Pp 155e9a56ad5SMark MurrayIf the salt begins with the string 156e9a56ad5SMark Murray.Fa $digit$ 157e9a56ad5SMark Murraythen the Modular Crypt Format is used. The 158e9a56ad5SMark Murray.Fa digit 159e9a56ad5SMark Murrayrepresents which algorithm is used in encryption. Following the token is 160e9a56ad5SMark Murraythe actual salt to use in the encryption. The length of the salt is limited 161e9a56ad5SMark Murrayto 16 characters--because the length of the returned output is also limited 162e9a56ad5SMark Murray(_PASSWORD_LEN). The salt must be terminated with the end of the string 163e9a56ad5SMark Murray(NULL) or a dollar sign. Any characters after the dollar sign are ignored. 164e9a56ad5SMark Murray.Pp 165e9a56ad5SMark MurrayCurrently supported algorithms are: 166e9a56ad5SMark Murray.Pp 167e9a56ad5SMark Murray.Bl -tag -width 012345678 -compact -offset indent 168e9a56ad5SMark Murray.It 1 169e9a56ad5SMark MurrayMD5 170e9a56ad5SMark Murray.El 171e9a56ad5SMark Murray.Pp 172e9a56ad5SMark MurrayOther crypt formats may be easilly added. An example salt would be: 173e9a56ad5SMark Murray.Bl -tag -offset indent 174e9a56ad5SMark Murray.It Cm "$3$thesalt$rest" 175e9a56ad5SMark Murray.El 176e9a56ad5SMark Murray.Pp 177e9a56ad5SMark Murray.Ss "Traditional" crypt: 178e9a56ad5SMark Murray.Pp 179f45f23ddSAlexey ZelkinThe algorithm used will depend upon whether 180f45f23ddSAlexey Zelkin.Tn DES 181f45f23ddSAlexey Zelkinis installed or not. If it is, 182f45f23ddSAlexey Zelkin.Tn DES 183f45f23ddSAlexey Zelkinwill be used. Otherwise, the best algorithm is used, which is currently 184e9a56ad5SMark Murray.\" 185e9a56ad5SMark Murray.\" NOTICE: Also make sure to update this 186e9a56ad5SMark Murray.\" 18700587201SMark MurrayMD5. 188e9a56ad5SMark Murray.Pp 189e9a56ad5SMark MurrayHow the salt is used will depend upon the algorithm for the hash. For 190e9a56ad5SMark Murraybest results, specify at least two characters of salt. 191e9a56ad5SMark Murray.Sh RETURN VALUES 192e9a56ad5SMark Murray.Pp 193e9a56ad5SMark Murray.Fn crypt 194e9a56ad5SMark Murrayreturns a pointer to the encrypted value on success, and NULL on failure. 195e9a56ad5SMark MurrayNote: this is not a standard behaviour, AT&T 196e9a56ad5SMark Murray.Fn crypt 197e9a56ad5SMark Murraywill always return a pointer to a string. 198e9a56ad5SMark Murray.Sh SEE ALSO 199e9a56ad5SMark Murray.Xr login 1 , 200e9a56ad5SMark Murray.Xr passwd 1 , 20100587201SMark Murray.Xr cipher 3 , 202e9a56ad5SMark Murray.Xr getpass 3 , 203e9a56ad5SMark Murray.Xr passwd 5 , 204e9a56ad5SMark Murray.Sh BUGS 205e9a56ad5SMark MurrayThe 206e9a56ad5SMark Murray.Fn crypt 207e9a56ad5SMark Murrayfunction returns a pointer to static data, and subsequent calls to 208e9a56ad5SMark Murray.Fn crypt 209e9a56ad5SMark Murraywill modify the same data. 210e9a56ad5SMark Murray.Sh HISTORY 211e9a56ad5SMark MurrayA rotor-based 212e9a56ad5SMark Murray.Fn crypt 213e9a56ad5SMark Murrayfunction appeared in 214e9a56ad5SMark Murray.At v6 . 215e9a56ad5SMark MurrayThe current style 216e9a56ad5SMark Murray.Fn crypt 217e9a56ad5SMark Murrayfirst appeared in 218e9a56ad5SMark Murray.At v7 . 219e9a56ad5SMark Murray.Pp 220f45f23ddSAlexey ZelkinThe 221f45f23ddSAlexey Zelkin.Tn DES 222f45f23ddSAlexey Zelkinsection of the code (FreeSec 1.0) was developed outside the United 223f45f23ddSAlexey ZelkinStates of America as an unencumbered replacement for the U.S.-only 224f45f23ddSAlexey Zelkin.Nx 225e9a56ad5SMark Murraylibcrypt encryption library. 226e9a56ad5SMark MurrayUsers should be aware that this code (and programs staticly linked with it) 227e9a56ad5SMark Murraymay not be exported from the U.S., although it apparently can be imported. 228e9a56ad5SMark Murray.Sh AUTHORS 229f45f23ddSAlexey ZelkinOriginally written by 230f45f23ddSAlexey Zelkin.An David Burren Aq davidb@werj.com.au , 231f45f23ddSAlexey Zelkinlater additions and changes by 232f45f23ddSAlexey Zelkin.An Poul-henning Kamp , 233f45f23ddSAlexey Zelkin.An Mark R V Murray 234f45f23ddSAlexey Zelkinand 235f45f23ddSAlexey Zelkin.An Kris Kennaway . 236