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Crypt
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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