1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
|
<!--startcut ======================================================= -->
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN">
<html>
<head>
<META NAME="generator" CONTENT="lgazmail v1.3F.f">
<TITLE>The Answer Gang 71: "crypt" function in Linux</TITLE>
</HEAD><BODY BGCOLOR="#FFFFFF" TEXT="#000000"
LINK="#3366FF" VLINK="#A000A0">
<!-- ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: -->
<P> <hr>
<CENTER>
<!-- *** BEGIN navbar *** -->
<!-- *** END navbar *** -->
</CENTER>
</p>
<P> <hr>
<!-- begin tagnav ::::::::::::::::::::::::::::::::::::::::::::::::::-->
<p align="center">
<table width="100%" border="0"><tr>
<td align="right" valign="center"
><IMG ALT="" SRC="../../gx/navbar/left.jpg"
WIDTH="14" HEIGHT="45" BORDER="0" ALIGN="middle" border="0"
><A HREF="..//"
><IMG SRC="../../gx/navbar/toc.jpg" align="middle"
ALT="[ Table Of Contents ]" border="0"></A
><A HREF="../lg_answer71.html"
><IMG SRC="../../gx/dennis/answertoc.jpg" align="middle"
ALT="[ Answer Guy Current Index ]" border="0"></A></td>
<td align="center" valign="center"><A HREF="../lg_answer71.html#greeting"><img align="middle"
src="../../gx/dennis/smily.gif" alt="greetings" border="0"></A>
<A HREF="1.html">1</A>
<A HREF="2.html">2</A>
<A HREF="3.html">3</A>
<A HREF="4.html">4</A>
<A HREF="5.html">5</A>
<A HREF="6.html">6</A>
<A HREF="7.html">7</A>
<A HREF="8.html">8</A>
</td>
<td align="left" valign="center"><A HREF="../../tag/kb.html"
><IMG SRC="../../gx/dennis/answerpast.jpg" align="middle"
ALT="[ Index of Past Answers ]" border="0"></A
><IMG ALT="" SRC="../../gx/navbar/right.jpg" align="middle"
WIDTH="14" HEIGHT="45" BORDER="0"></td></tr></table>
</p>
<!-- end tagnav ::::::::::::::::::::::::::::::::::::::::::::::::::::-->
<P> <hr> <P>
<!-- ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: -->
<center>
<H1><A NAME="answer">
<img src="../../gx/dennis/qbubble.gif" alt="(?)"
border="0" align="middle">
<font color="#B03060">The Answer Gang</font>
<img src="../../gx/dennis/bbubble.gif" alt="(!)"
border="0" align="middle">
</A></H1>
<BR>
<H4>By Jim Dennis, Ben Okopnik, Dan Wilder, Breen, Chris, and the Gang,
the Editors of Linux Gazette...
and You!
<br>Send questions (or interesting answers) to
<a href="mailto:linux-questions-only@ssc.com">linux-questions-only@ssc.com</a>
</H4>
<p><em><font color="#990000">There is no guarantee that your questions
here will <b>ever</b> be answered. Readers at confidential sites
must provide permission to publish. However, you can be published
anonymously - just let us know!
</font></em></p>
</center>
<p><hr><p>
<!-- endcut ======================================================= -->
<!-- begin 2 -->
<H3 align="left"><img src="../../gx/dennis/qbubble.gif"
height="50" width="60" alt="(?) " border="0"
>"crypt" function in Linux</H3>
<p><strong>From Ben Okopnik
</strong></p>
<p align="right"><strong>Answered By
<p></strong></p>
<BLOCKQUOTE>
Just a little while ago, I needed to use the "crypt" program, so
well-known in other Unices, to encode a text file (for those of you
unfamiliar with it, it encrypts the contents of a file using a password
that you supply. A fairly useful little utility when you want just a bit
of added security on a publicly-readable file.) Imagine my surprise when
I found that Linux does not have one! Once again, it's Perl to the rescue.
</BLOCKQUOTE>
<BLOCKQUOTE>
This version follows the syntax of the original "crypt", although
I'm certain that the algorithm is different. The encryption and the
decryption are symmetric, meaning that the same syntax is used for both
(with the obvious exception of the relevant filenames):
</BLOCKQUOTE>
<blockquote><code><font color="#000033"><br># This encrypts the contents of "mysecret.txt" using "iAMw0tIam" as the
<br># password and saves the results to "mysecret.encrypted".
<br>crypt iAMw0tIam < mysecret.txt > mysecret.encrypted
<br>
<br># This prints out the decrypted contents of "mysecret.encrypted" to the
<br># screen.
<br>crypt iAMw0tIam < mysecret.encrypted
<br>
<br># This decrypts the contents of "mysecret.encrypted" and writes the results
<br># to "mysecret.decrypted".
<br>crypt iAMw0tIam < mysecret.encrypted > mysecret.decrypted
</font></code></blockquote>
<BLOCKQUOTE>
Long passwords are preferable to short ones for better security;
"crypt" accepts them without a problem, provided that any password
containing spaces or other "weird characters" is quoted (preferably
in single quotes).
</BLOCKQUOTE>
<blockquote><code><font color="#000033"><br> crypt 'Praeterea, censeo Carthaginem esse delendam.' < file > file.enc
</font></code></blockquote>
<BLOCKQUOTE>
As always, bug reports, comments, and piles of diamonds are welcome.
<IMG SRC="../../gx/dennis/smily.gif" ALT=":)"
height="24" width="20" align="middle">
</BLOCKQUOTE>
<p align="center">See attached <tt><a href="../misc/tag/crypt.perl.txt">crypt.perl.txt</a></tt></p>
<BLOCKQUOTE>
Ben Okopnik
</BLOCKQUOTE>
<!-- end 2 -->
<!--startcut ======================================================= -->
<P> <hr> </p>
<!-- *** BEGIN copyright *** -->
<H5 align="center">This page edited and maintained by the Editors
of <I>Linux Gazette</I>
<a href="http://www.linuxgazette.com/copying.html"
>Copyright ©</a> 2001
<BR>Published in issue 71 of <I>Linux Gazette</I> October 2001</H5>
<H6 ALIGN="center">HTML script maintained by
<A HREF="mailto:star@starshine.org">Heather Stern</a> of
Starshine Technical Services,
<A HREF="http://www.starshine.org/">http://www.starshine.org/</A>
</H6>
<!-- *** END copyright *** -->
<P> <hr>
<!-- begin tagnav ::::::::::::::::::::::::::::::::::::::::::::::::::-->
<p align="center">
<table width="100%" border="0"><tr>
<td align="right" valign="center"
><IMG ALT="" SRC="../../gx/navbar/left.jpg"
WIDTH="14" HEIGHT="45" BORDER="0" ALIGN="middle" border="0"
><A HREF="..//"
><IMG SRC="../../gx/navbar/toc.jpg" align="middle"
ALT="[ Table Of Contents ]" border="0"></A
><A HREF="../lg_answer71.html"
><IMG SRC="../../gx/dennis/answertoc.jpg" align="middle"
ALT="[ Answer Guy Current Index ]" border="0"></A></td>
<td align="center" valign="center"><A HREF="../lg_answer71.html#greeting"><img align="middle"
src="../../gx/dennis/smily.gif" alt="greetings" border="0"></A>
<A HREF="1.html">1</A>
<A HREF="2.html">2</A>
<A HREF="3.html">3</A>
<A HREF="4.html">4</A>
<A HREF="5.html">5</A>
<A HREF="6.html">6</A>
<A HREF="7.html">7</A>
<A HREF="8.html">8</A>
</td>
<td align="left" valign="center"><A HREF="../../tag/kb.html"
><IMG SRC="../../gx/dennis/answerpast.jpg" align="middle"
ALT="[ Index of Past Answers ]" border="0"></A
><IMG ALT="" SRC="../../gx/navbar/right.jpg" align="middle"
WIDTH="14" HEIGHT="45" BORDER="0"></td></tr></table>
</p>
<!-- end tagnav ::::::::::::::::::::::::::::::::::::::::::::::::::::-->
<P> <hr>
<CENTER>
<!-- *** BEGIN navbar *** -->
<!-- *** END navbar *** -->
</CENTER>
</p>
<!-- ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: -->
</BODY></HTML>
<!--endcut ========================================================= -->
|
