1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
|
#
# 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 = '2.05';
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
|
