1# 2# Copyright (C) 1995, 1996 Systemics Ltd (http://www.systemics.com/) 3# All rights reserved. 4# 5# Modifications are Copyright (c) 2000, W3Works, LLC 6# All Rights Reserved. 7 8package Crypt::DES; 9 10require Exporter; 11require DynaLoader; 12use vars qw($VERSION @ISA @EXPORT @EXPORT_OK); 13 14@ISA = qw(Exporter DynaLoader); 15 16# Items to export into callers namespace by default 17@EXPORT = qw(); 18 19# Other items we are prepared to export if requested 20@EXPORT_OK = qw(); 21 22$VERSION = '2.07'; 23bootstrap Crypt::DES $VERSION; 24 25use strict; 26use Carp; 27 28sub usage 29{ 30 my ($package, $filename, $line, $subr) = caller(1); 31 $Carp::CarpLevel = 2; 32 croak "Usage: $subr(@_)"; 33} 34 35 36sub blocksize { 8; } 37sub keysize { 8; } 38 39sub new 40{ 41 usage("new DES key") unless @_ == 2; 42 43 my $type = shift; 44 my $self = {}; 45 bless $self, $type; 46 47 $self->{'ks'} = Crypt::DES::expand_key(shift); 48 49 return $self; 50} 51 52sub encrypt 53{ 54 usage("encrypt data[8 bytes]") unless @_ == 2; 55 56 my ($self,$data) = @_; 57 return Crypt::DES::crypt($data, $data, $self->{'ks'}, 1); 58} 59 60sub decrypt 61{ 62 usage("decrypt data[8 bytes]") unless @_ == 2; 63 64 my ($self,$data) = @_; 65 return Crypt::DES::crypt($data, $data, $self->{'ks'}, 0); 66} 67 681; 69 70__END__ 71 72=head1 NAME 73 74Crypt::DES - Perl DES encryption module 75 76=head1 SYNOPSIS 77 78 use Crypt::DES; 79 80 81=head1 DESCRIPTION 82 83The module implements the Crypt::CBC interface, 84which has the following methods 85 86=over 4 87 88=item blocksize 89=item keysize 90=item encrypt 91=item decrypt 92 93=back 94 95=head1 FUNCTIONS 96 97=over 4 98 99=item blocksize 100 101Returns the size (in bytes) of the block cipher. 102 103=item keysize 104 105Returns the size (in bytes) of the key. Optimal size is 8 bytes. 106 107=item new 108 109 my $cipher = new Crypt::DES $key; 110 111This creates a new Crypt::DES BlockCipher object, using $key, 112where $key is a key of C<keysize()> bytes. 113 114=item encrypt 115 116 my $cipher = new Crypt::DES $key; 117 my $ciphertext = $cipher->encrypt($plaintext); 118 119This function encrypts $plaintext and returns the $ciphertext 120where $plaintext and $ciphertext should be of C<blocksize()> bytes. 121 122=item decrypt 123 124 my $cipher = new Crypt::DES $key; 125 my $plaintext = $cipher->decrypt($ciphertext); 126 127This function decrypts $ciphertext and returns the $plaintext 128where $plaintext and $ciphertext should be of C<blocksize()> bytes. 129 130=back 131 132=head1 EXAMPLE 133 134 my $key = pack("H16", "0123456789ABCDEF"); 135 my $cipher = new Crypt::DES $key; 136 my $ciphertext = $cipher->encrypt("plaintex"); # NB - 8 bytes 137 print unpack("H16", $ciphertext), "\n"; 138 139=head1 NOTES 140 141Do note that DES only uses 8 byte keys and only works on 8 byte data 142blocks. If you're intending to encrypt larger blocks or entire files, 143please use Crypt::CBC in conjunction with this module. See the 144Crypt::CBC documentation for proper syntax and use. 145 146Also note that the DES algorithm is, by today's standard, weak 147encryption. Crypt::Blowfish is highly recommended if you're 148interested in using strong encryption and a faster algorithm. 149 150=head1 SEE ALSO 151 152Crypt::Blowfish 153Crypt::IDEA 154 155Bruce Schneier, I<Applied Cryptography>, 1995, Second Edition, 156published by John Wiley & Sons, Inc. 157 158=head1 COPYRIGHT 159 160The implementation of the DES algorithm was developed by, 161and is copyright of, Eric Young (eay@mincom.oz.au). 162Other parts of the perl extension and module are 163copyright of Systemics Ltd ( http://www.systemics.com/ ). 164Cross-platform work and packaging for single algorithm 165distribution is copyright of W3Works, LLC. 166 167=head1 MAINTAINER 168 169This single-algorithm package and cross-platform code is 170maintained by Dave Paris <amused@pobox.com>. 171 172=cut 173