.\" Michael Haardt (michael@cantor.informatik.rwth.aachen.de) Sat Sep  3 22:00:30 MET DST 1994
.\"
.\" This is free documentation; you can redistribute it and/or
.\" modify it under the terms of the GNU General Public License as
.\" published by the Free Software Foundation; either version 2 of
.\" the License, or (at your option) any later version.
.\"
.\" The GNU General Public License's references to "object code"
.\" and "executables" are to be interpreted as the output of any
.\" document formatting or typesetting system, including
.\" intermediate and printed output.
.\"
.\" This manual is distributed in the hope that it will be useful,
.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
.\" GNU General Public License for more details.
.\"
.\" You should have received a copy of the GNU General Public
.\" License along with this manual; if not, write to the Free
.\" Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111,
.\" USA.
.\"
.\" Sun Feb 19 21:32:25 1995, faith@cs.unc.edu edited details away
.\"
.\" TO DO: This manual page should go more into detail how DES is perturbed, 
.\" which string will be encrypted, and what determines the repetition factor.
.\" Is a simple repetition using ECB used, or something more advanced?  I hope
.\" the presented explanations are at least better than nothing, but by no
.\" means enough.
.\"
.\" added _XOPEN_SOURCE, aeb, 970705
.\" added GNU MD5 stuff, aeb, 011223
.\"
.\" Japanese Version Copyright (c) 1998 Hiroaki Nagoya and MAEHARA Kouichi all rights reserved.
.\" Translated Sun Sep 27 JST 1998 by Hiroaki Nagoya <nagoya@cc.hit-u.ac.jp> and MAEHARA Kouichi <maeharak@kw.netlaputa.ne.jp>
.\" Updated Sat Jan 19 JST 2002 by Kentaro Shirakata <argrath@ub32.org>
.\"
.\"WORD: encryption Ź沽
.\"WORD: key 
.\" "
.TH CRYPT 3 2001-12-23 "" "Library functions"
.SH ̾
crypt \- ѥɤȥǡΰŹ沽
.SH 
.B #define _XOPEN_SOURCE
.br
.B #include <unistd.h>
.sp
.BI "char *crypt(const char *" key ", const char *" salt );
.SH 
.B crypt
ϥѥɰŹ沽ؿǤ롣
õΥϡɥˤ˸褦(¾ˤ⤤)
ѹ Data Encryption Standard 르ꥺ򸵤ˤƤ롣
.PP
.I key
ϥ桼ϤѥɤǤ롣
.PP
.I salt
Ͻ
[\fBa\fP\(en\fBzA\fP\(en\fBZ0\fP\(en\fB9./\fP]
Ф줿 2 ʸʸǤ롣
ʸϥ르ꥺνϤ 4096 ̤ˤ𤹤Τ˻Ȥ롣
.PP
.IR key
κǽ 8 ʸγʸ鲼 7 ӥåȤȤä 56 ӥåȤθ롣
 56 ӥåȤθʸ(դĤϤ٤ 0 ʸ)
򷫤֤Ź沽ΤѤ롣
֤ͤϰŹ沽줿ѥɤؤΥݥ󥿤ǡ13 ΰǽ ASCII ʸ
ʤ(ǽ 2 ʸ salt Τ)
֤ͤϡؿƽФΤӤ˾񤭤ŪʥǡؤΥݥ󥿤Ǥ롣
.PP
ٹ: ֤
.if t 2\s-2\u56\s0\d
.if n 2**56
= 7.2e16 βǽͤ롣
θ֤õ϶Ϥ׻ȤвǽǤ롣ޤ
.BR crack (1)
Τ褦ʥեȥϤθ֤ǡ¿οͤ˥ѥɤȤ
Ȥ褦ʸˤĤƤõǽǤ롣
椨ѥɤ򤹤ȤˤϡʤȤ⡢
Ū˻Ȥñ̾򤱤٤Ǥ롣
.BR passwd (1)
Ȥˤϥå줦ѥɤˤĤƤθ򤹤뤳Ȥ
侩롣
.PP
DES 르ꥺˤϤĤʤꡢˤäƥѥǧڰʳ
.BR crypt (3)
ȤΤϤؤ褯ʤȤʤäƤ롣⤷
.BR crypt (3)
ŹץȤ˻ȤȤƤäƤʤСϤ᤿ۤ
褤Ź沽ˤĤƤΤ褤ܤïǤǤ DES 饤֥ΤҤȤĤ
ˤ٤
.SH ֤
Ź沽줿ѥɤؤΥݥ󥿡֤롣
顼ξˤ NULL ֤롣
.SH 顼
.TP
.B ENOSYS
.B crypt
ؿƤʤ¿ʬꥫ͢еΤˡ
.\" Υ٥ξܺ٤ϤΥޥ˥奢ˤɬפʤ
.\" (: ʲ MAEHARA Kouichi <maeharak@kw.netlaputa.ne.jp> )
.\" .PP
.\"ʿʸ P  K Ǥä DES ѤưŹ沽Ȥη̤ΰŹʸ
.\" C ȤʤСP Ф 2 Ūʿʸ P'  K 
.\"ФƱͤŪʸ K' ѤưŹ沽 C ФƤϤ
.\"ŪʰŹʸ C' Ȥʤ롣
.\".PP
.\"DES ˤ븰ѷˤơ˹ФƼ夤¸ߤ롣褯
.\"Τ줿ͤĤμ夤 0101010101010101fefefefefefefefe
.\"1f1f1f1f0e0e0e0ee0e0e0e0f1f1f1f1 ǤꤳλѤ򤱤ʤ
.\"ʤʤ
.\".PP
.\"ƱΰŹ沽̤ƳƤޤϻȤΤ夤⤢롣
.\"ĤθλѤϤϤ򤱤٤Ǥ롣
.\"櫓ʤȤˤɤʸΤĴ٤ʤ
.\"
.\".PP
.\"ü˾ĹǤǡϡ
.\".BR crypt (3) 
.\"Τ褦
.\".I "Źɽ(codebook)"
.\"⡼ɤǼƤ DES ˤŹ沽ˤƤϥȥ֥ΤȤȤ
.\"롣
.\".BR crypt (3)
.\"Ϥ̤ꡢѥɤǧڤŪˤΤѤ٤ΤǤꡢ
.\"ǡΰŹ沽ġȤѤƤϤʤʤ
.\".PP
.\" S-box ΡƬĤν bit ϡ bit δؿ
.\"Ȥɽ魯ȤǤ롣Τ褦 S-box ƱϤФƤ
.\"ʬŪƱŹ沽̤ƤޤȤ¸ˤäƤ餫ˤ
.\"Ƥ롣ϡȰݾ(NSA) DES ˤŹǡβɤǽ
.\"ˤ뤿ߤ΢ʤΤǤϤʤȵƤ롣
.\".PP
.\"äͳˤꡢcrypt() ѤŹ沽ǡ뤳
.\"ϰǤϤʤǧ٤ʤΤǤ롣
.\"
.SH "GNU ĥ"
δؿ glibc2 ǤϰʲΤ褦ʳĥǽ롣
⤷
.I salt
ʸκǽ 3 ʸ "$1$" Ǥꡢ 8 ʸθ塢
Ǹ "$" ǽäƤ(ϤʤƤ褤)硢
DES ǤϤʤ MD5 ȤäŹ沽르ꥺबѤ졢
ϤϺ 34 ХȤȤʤ롣
Ϥ "$1$<string>$" ηǤꡢ
"<string>"  salt ˤ "$1$" ˰³ 8 ʸʲʸ
θ [\fBa\fP\(en\fBzA\fP\(en\fBZ0\fP\(en\fB9./\fP] ν礫
Ф 22 ХȤǤ롣
ξ硢(ǽ 8 ʸǤϤʤ)Τ̣롣
.LP
δؿѤץ -lcrypt ץĤ
󥯤ʤФʤʤ
.SH 
SVID, X/OPEN, BSD 4.3, POSIX 1003.1-2001
.SH Ϣ
.BR login (1),
.BR passwd (1),
.BR encrypt (3),
.BR getpass (3),
.BR passwd (5)