1RC4(3)                User Contributed Perl Documentation               RC4(3)
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NAME

6       Crypt::RC4 - Perl implementation of the RC4 encryption algorithm
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SYNOPSIS

9       # Functional Style
10         use Crypt::RC4;
11         $encrypted = RC4( $passphrase, $plaintext );
12         $decrypt = RC4( $passphrase, $encrypted );
13
14       # OO Style
15         use Crypt::RC4;
16         $ref = Crypt::RC4->new( $passphrase );
17         $encrypted = $ref->RC4( $plaintext );
18
19         $ref2 = Crypt::RC4->new( $passphrase );
20         $decrypted = $ref2->RC4( $encrypted );
21
22       # process an entire file, one line at a time # (Warning: Encrypted file
23       leaks line lengths.)
24         $ref3 = Crypt::RC4->new( $passphrase );
25         while (<FILE>) {
26             chomp;
27             print $ref3->RC4($_), "\n";
28         }
29

DESCRIPTION

31       A simple implementation of the RC4 algorithm, developed by RSA
32       Security, Inc. Here is the description from RSA's website:
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34       RC4 is a stream cipher designed by Rivest for RSA Data Security (now
35       RSA Security). It is a variable key-size stream cipher with byte-
36       oriented operations. The algorithm is based on the use of a random
37       permutation. Analysis shows that the period of the cipher is
38       overwhelmingly likely to be greater than 10100. Eight to sixteen
39       machine operations are required per output byte, and the cipher can be
40       expected to run very quickly in software. Independent analysts have
41       scrutinized the algorithm and it is considered secure.
42
43       Based substantially on the "RC4 in 3 lines of perl" found at
44       http://www.cypherspace.org
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46       A major bug in v1.0 was fixed by David Hook (dgh@wumpus.com.au).
47       Thanks, David.
48

AUTHOR

50       Kurt Kincaid (sifukurt@yahoo.com) Ronald Rivest for RSA Security, Inc.
51

BUGS

53       Disclaimer: Strictly speaking, this module uses the "alleged" RC4
54       algorithm. The Algorithm known as "RC4" is a trademark of RSA Security
55       Inc., and this document makes no claims one way or another that this is
56       the correct algorithm, and further, make no claims about the quality of
57       the source code nor any licensing requirements for commercial use.
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59       There's nothing preventing you from using this module in an insecure
60       way which leaks information. For example, encrypting multilple messages
61       with the same passphrase may allow an attacker to decode all of them
62       with little effort, even though they'll appear to be secured. If
63       serious crypto is your goal, be careful. Be very careful.
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65       It's a pure-Perl implementation, so that rating of "Eight to sixteen
66       machine operations" is good for nothing but a good laugh.  If
67       encryption and decryption are a bottleneck for you, please re-write
68       this module to use native code wherever practical.
69

LICENSE

71       This is free software and may be modified and/or redistributed under
72       the same terms as Perl itself.
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SEE ALSO

75       perl, <http://www.cypherspace.org>, <http://www.rsasecurity.com>,
76       <http://www.achtung.com/crypto/rc4.html>,
77       <http://www.columbia.edu/~ariel/ssleay/rrc4.html>
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81perl v5.34.0                      2021-07-22                            RC4(3)
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