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database/perl/vendor/lib/Crypt/DES.pm

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