File Coverage

blib/lib/Crypt/Eksblowfish.pm

Criterion	Covered	Total	%
statement	12	12	100.0
branch			n/a
condition			n/a
subroutine	4	4	100.0
pod			n/a
total	16	16	100.0

line	stmt	sub	time	code
1				=head1 NAME
2
3				Crypt::Eksblowfish - the Eksblowfish block cipher
4
5				=head1 SYNOPSIS
6
7				use Crypt::Eksblowfish;
8
9				$block_size = Crypt::Eksblowfish->blocksize;
10
11				$cipher = Crypt::Eksblowfish->new(8, $salt, $key);
12
13				$block_size = $cipher->blocksize;
14				$ciphertext = $cipher->encrypt($plaintext);
15				$plaintext = $cipher->decrypt($ciphertext);
16
17				$p_array = $cipher->p_array;
18				$s_boxes = $cipher->s_boxes;
19				if($cipher->is_weak) { ...
20
21				=head1 DESCRIPTION
22
23				An object of this type encapsulates a keyed instance of the Eksblowfish
24				block cipher, ready to encrypt and decrypt.
25
26				Eksblowfish is a variant of the Blowfish cipher, modified to make
27				the key setup very expensive. ("Eks" stands for "expensive key
28				schedule".) This doesn't make it significantly cryptographically
29				stronger, but is intended to hinder brute-force attacks. It also
30				makes it unsuitable for any application requiring key agility. It was
31				designed by Niels Provos and David Mazieres for password hashing in
32				OpenBSD. See L for the hash algorithm.
33				See L for the unmodified Blowfish cipher.
34
35				Eksblowfish is a parameterised (family-keyed) cipher. It takes a cost
36				parameter that controls how expensive the key scheduling is. It also
37				takes a family key, known as the "salt". Cost and salt parameters
38				together define a cipher family. Within each family, a key determines an
39				encryption function in the usual way. See L
40				for a way to encapsulate an Eksblowfish cipher family.
41
42				=cut
43
44				package Crypt::Eksblowfish;
45
46	6	6	96434	{ use 5.006; }
	6		22
	6		257
47	6	6	32	use warnings;
	6		10
	6		190
48	6	6	29	use strict;
	6		11
	6		298
49
50				our $VERSION = "0.009";
51
52	6	6	6524	use parent "Crypt::Eksblowfish::Subkeyed";
	6		2864
	6		35
53
54				die "mismatched versions of Crypt::Eksblowfish modules"
55				unless $Crypt::Eksblowfish::Subkeyed::VERSION eq $VERSION;
56
57				=head1 CLASS METHODS
58
59				=over
60
61				=item Crypt::Eksblowfish->blocksize
62
63				Returns 8, indicating the Eksblowfish block size of 8 octets. This method
64				may be called on either the class or an instance.
65
66				=back
67
68				=head1 CONSTRUCTOR
69
70				=over
71
72				=item Crypt::Eksblowfish->new(COST, SALT, KEY)
73
74				Performs key setup on a new instance of the Eksblowfish algorithm,
75				returning the keyed state. The KEY may be any length from 1 octet to
76				72 octets inclusive. The SALT is a family key, and must be exactly
77				16 octets. COST is an integer parameter controlling the expense of
78				keying: the number of operations in key setup is proportional to 2^COST.
79				All three parameters influence all the subkeys; changing any of them
80				produces a different encryption function.
81
82				Due to the mandatory family-keying parameters (COST and SALT), this
83				constructor does not match the interface expected by C
84				and similar crypto plumbing modules. To
85				use Eksblowfish with them it is necessary to have an object that
86				encapsulates a cipher family and provides a constructor that takes only a
87				key argument. That facility is supplied by C.
88
89				=back
90
91				=head1 METHODS
92
93				=over
94
95				=item $cipher->blocksize
96
97				Returns 8, indicating the Eksblowfish block size of 8 octets. This method
98				may be called on either the class or an instance.
99
100				=item $cipher->encrypt(PLAINTEXT)
101
102				PLAINTEXT must be exactly eight octets. The block is encrypted, and
103				the ciphertext is returned.
104
105				=item $cipher->decrypt(CIPHERTEXT)
106
107				CIPHERTEXT must be exactly eight octets. The block is decrypted, and
108				the plaintext is returned.
109
110				=item $cipher->p_array
111
112				=item $cipher->s_boxes
113
114				These methods extract the subkeys from the keyed cipher.
115				This is not required in ordinary operation. See the superclass
116				L for details.
117
118				=item $cipher->is_weak
119
120				This method checks whether the cipher has been keyed with a weak key.
121				It may be desired to avoid using weak keys. See the superclass
122				L for details.
123
124				=back
125
126				=head1 SEE ALSO
127
128				L,
129				L,
130				L,
131				L,
132				L
133
134				=head1 AUTHOR
135
136				Eksblowfish guts originally by Solar Designer (solar at openwall.com).
137
138				Modifications and Perl interface by Andrew Main (Zefram)
139				.
140
141				=head1 COPYRIGHT
142
143				Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011
144				Andrew Main (Zefram)
145
146				The original Eksblowfish code (in the form of crypt()) from which
147				this module is derived is in the public domain. It may be found at
148				L.
149
150				=head1 LICENSE
151
152				This module is free software; you can redistribute it and/or modify it
153				under the same terms as Perl itself.
154
155				=cut
156
157				1;