1Simple(3)             User Contributed Perl Documentation            Simple(3)
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NAME

6       Crypt::Simple - encrypt stuff simply
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SYNOPSIS

9         use Crypt::Simple;
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11         my $data = encrypt(@stuff);
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13         my @same_stuff = decrypt($data);
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DESCRIPTION

16       Maybe you have a web application and you need to store some session
17       data at the client side (in a cookie or hidden form fields) but you
18       don't want the user to be able to mess with the data.  Maybe you want
19       to save secret information to a text file.  Maybe you have better ideas
20       of what to do with encrypted stuff!
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22       This little module will convert all your data into nice base64 text
23       that you can save in a text file, send in an email, store in a cookie
24       or web page, or bounce around the Net.  The data you encrypt can be as
25       simple or as complicated as you like.
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KEY

28       If you don't pass any options when using "Crypt::Simple" we will gener‐
29       ate a key for you based on the name of your module that uses this one.
30       In many cases this works fine, but you may want more control over the
31       key.  Here's how:
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33       use Crypt::Simple passphrase => 'pass phrase';
34           The MD5 hash of the text string "pass phrase" is used as the key.
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36       use Crypt::Simple prompt => 'Please type the magic words';
37           The user is prompted to enter a passphrase, and the MD5 hash of the
38           entered text is used as the key.
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40       use Crypt::Simple passfile => '/home/marty/secret';
41           The contents of the file /home/marty/secret are used as the pass
42           phrase: the MD5 hash of the file is used as the key.
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44       use Crypt::Simple file => '/home/marty/noise';
45           The contents of the file /home/marty/noise are directly used as the
46           key.
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INTERNALS

49       "Crypt::Simple" is really just a wrapper round a few other useful Perl
50       modules: you may want to read the documentation for these modules too.
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52       We use "FreezeThaw" to squish all your data into a concise textual rep‐
53       resentation.  We use "Compress::Zlib" to compress this string, and then
54       use "Crypt::Blowfish" in a home-brew CBC mode to perform the encryp‐
55       tion.  Somewhere in this process we also add a MD5 digest (using
56       "Digest::MD5").  Then we throw the whole thing through "MIME::Base64"
57       to produce a nice bit of text for you to play with.
58
59       Decryption, obviously, is the reverse of this process.
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WARNING

62       Governments throughout the world do not like encryption because it
63       makes it difficult for them to look at all your stuff.  Each country
64       has a different policy designed to stop you using encryption: some gov‐
65       ernments are honest enough to make it illegal; some think it is a dan‐
66       gerous weapon; some insist that you are free to encrypt, but only evil
67       people would want to; some make confusing and contradictory laws
68       because they try to do all of the above.
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70       Although this modules itself does not include any encryption code, it
71       does use another module that contains encryption code, and this docu‐
72       mentation mentions encryption.  Downloading, using, or reading this
73       modules could be illegal where you live.
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AUTHOR

76       Marty Pauley <marty@kasei.com>
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79         Copyright (C) 2001 Kasei Limited
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81         This program is free software; you can redistribute it and/or modify it under
82         the terms of the GNU General Public License; either version 2 of the License,
83         or (at your option) any later version.
84
85         This program is distributed in the hope that it will be useful, but WITHOUT
86         ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
87         FOR A PARTICULAR PURPOSE.
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91perl v5.8.8                       2002-09-23                         Simple(3)
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