114 lines
2.7 KiB
Perl
114 lines
2.7 KiB
Perl
package Crypt::CAST5;
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require 5.004;
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use strict;
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use DynaLoader;
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use vars qw( $VERSION @ISA );
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$VERSION = "0.05";
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@ISA = qw( DynaLoader );
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bootstrap Crypt::CAST5 $VERSION;
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1 # end Crypt::CAST5
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__END__
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=head1 NAME
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Crypt::CAST5 - CAST5 block cipher
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=head1 SYNOPSIS
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use Crypt::CBC;
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my $crypt = Crypt::CBC->new({
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key => "secret key",
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cipher => "CAST5",
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});
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my $message = "All mimsy were the borogoves";
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my $ciphertext = $crypt->encrypt($message);
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print unpack("H*", $ciphertext), "\n";
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my $plaintext = $crypt->decrypt($ciphertext);
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print $plaintext, "\n";
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=head1 DESCRIPTION
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This module provides an implementation of the CAST5 block cipher using
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compiled C code for increased speed. CAST5 is also known as CAST-128. It
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is a product of the CAST design procedure developed by C. Adams and
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S. Tavares.
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The CAST5 cipher is available royalty-free.
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=head1 FUNCTIONS
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=head2 blocksize
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Returns the CAST5 block size, which is 8 bytes. This function exists
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so that Crypt::CAST5 can work with Crypt::CBC.
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=head2 keysize
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Returns the maximum CAST5 key size, 16 bytes.
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=head2 new
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$cast5 = Crypt::CAST5->new($key);
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Create a new encryption object. If the optional key parameter is given,
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it will be passed to the init() function.
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=head2 init
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$cast5->init($key);
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Set or change the encryption key to be used. The key must be from 40 bits
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(5 bytes) to 128 bits (16 bytes) in length. Note that if the key used is
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80 bits or less, encryption and decryption will be somewhat faster.
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It is best for the key to be random binary data, not something printable
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like a password. A message digest function may be useful for converting
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a password to an encryption key; see L<Digest::SHA1> or L<Digest::MD5>.
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Note that Crypt::CBC runs the given "key" through MD5 to get the actual
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encryption key.
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=head2 encrypt
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$ciphertext = $cast5->encrypt($plaintext);
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Encrypt a block of plaintext using the current encryption key, and return
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the corresponding ciphertext. The input must be 8 bytes long, and the output
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has the same length. Note that the encryption is in ECB mode, which means
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that it encrypts each block independently. That can leave you vulnerable
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to dictionary attacks, so it is generally best to use some form of chaining
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between blocks; see L<Crypt::CBC>.
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=head2 decrypt
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$plaintext = $cast5->decrypt($ciphertext);
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Decrypt the ciphertext and return the corresponding plaintext.
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=head1 SEE ALSO
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RFC 2144, "The CAST-128 Encryption Algorithm", C. Adams, May 1997
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L<Crypt::CBC>
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=head1 AUTHOR
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Bob Mathews, E<lt>bobmathews@alumni.calpoly.eduE<gt>
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=head1 COPYRIGHT AND LICENSE
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Copyright (C) 2002-2006 Bob Mathews
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This library is free software; you can redistribute it and/or modify
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it under the same terms as Perl itself.
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=cut
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