173 lines
3.4 KiB
Perl
173 lines
3.4 KiB
Perl
#
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# Copyright (C) 1995, 1996 Systemics Ltd (http://www.systemics.com/)
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# All rights reserved.
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#
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# Modifications are Copyright (c) 2000, W3Works, LLC
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# All Rights Reserved.
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package Crypt::DES;
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require Exporter;
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require DynaLoader;
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use vars qw($VERSION @ISA @EXPORT @EXPORT_OK);
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@ISA = qw(Exporter DynaLoader);
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# Items to export into callers namespace by default
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@EXPORT = qw();
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# Other items we are prepared to export if requested
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@EXPORT_OK = qw();
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$VERSION = '2.07';
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bootstrap Crypt::DES $VERSION;
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use strict;
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use Carp;
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sub usage
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{
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my ($package, $filename, $line, $subr) = caller(1);
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$Carp::CarpLevel = 2;
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croak "Usage: $subr(@_)";
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}
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sub blocksize { 8; }
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sub keysize { 8; }
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sub new
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{
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usage("new DES key") unless @_ == 2;
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my $type = shift;
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my $self = {};
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bless $self, $type;
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$self->{'ks'} = Crypt::DES::expand_key(shift);
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return $self;
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}
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sub encrypt
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{
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usage("encrypt data[8 bytes]") unless @_ == 2;
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my ($self,$data) = @_;
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return Crypt::DES::crypt($data, $data, $self->{'ks'}, 1);
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}
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sub decrypt
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{
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usage("decrypt data[8 bytes]") unless @_ == 2;
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my ($self,$data) = @_;
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return Crypt::DES::crypt($data, $data, $self->{'ks'}, 0);
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}
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1;
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__END__
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=head1 NAME
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Crypt::DES - Perl DES encryption module
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=head1 SYNOPSIS
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use Crypt::DES;
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=head1 DESCRIPTION
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The module implements the Crypt::CBC interface,
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which has the following methods
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=over 4
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=item blocksize
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=item keysize
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=item encrypt
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=item decrypt
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=back
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=head1 FUNCTIONS
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=over 4
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=item blocksize
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Returns the size (in bytes) of the block cipher.
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=item keysize
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Returns the size (in bytes) of the key. Optimal size is 8 bytes.
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=item new
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my $cipher = new Crypt::DES $key;
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This creates a new Crypt::DES BlockCipher object, using $key,
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where $key is a key of C<keysize()> bytes.
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=item encrypt
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my $cipher = new Crypt::DES $key;
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my $ciphertext = $cipher->encrypt($plaintext);
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This function encrypts $plaintext and returns the $ciphertext
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where $plaintext and $ciphertext should be of C<blocksize()> bytes.
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=item decrypt
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my $cipher = new Crypt::DES $key;
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my $plaintext = $cipher->decrypt($ciphertext);
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This function decrypts $ciphertext and returns the $plaintext
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where $plaintext and $ciphertext should be of C<blocksize()> bytes.
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=back
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=head1 EXAMPLE
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my $key = pack("H16", "0123456789ABCDEF");
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my $cipher = new Crypt::DES $key;
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my $ciphertext = $cipher->encrypt("plaintex"); # NB - 8 bytes
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print unpack("H16", $ciphertext), "\n";
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=head1 NOTES
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Do note that DES only uses 8 byte keys and only works on 8 byte data
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blocks. If you're intending to encrypt larger blocks or entire files,
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please use Crypt::CBC in conjunction with this module. See the
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Crypt::CBC documentation for proper syntax and use.
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Also note that the DES algorithm is, by today's standard, weak
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encryption. Crypt::Blowfish is highly recommended if you're
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interested in using strong encryption and a faster algorithm.
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=head1 SEE ALSO
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Crypt::Blowfish
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Crypt::IDEA
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Bruce Schneier, I<Applied Cryptography>, 1995, Second Edition,
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published by John Wiley & Sons, Inc.
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=head1 COPYRIGHT
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The implementation of the DES algorithm was developed by,
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and is copyright of, Eric Young (eay@mincom.oz.au).
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Other parts of the perl extension and module are
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copyright of Systemics Ltd ( http://www.systemics.com/ ).
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Cross-platform work and packaging for single algorithm
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distribution is copyright of W3Works, LLC.
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=head1 MAINTAINER
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This single-algorithm package and cross-platform code is
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maintained by Dave Paris <amused@pobox.com>.
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=cut
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