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
|
package Crypt::AuthEnc::GCM;
use strict;
use warnings;
our $VERSION = '0.079_007';
require Exporter; our @ISA = qw(Exporter); ### use Exporter 5.57 'import';
our %EXPORT_TAGS = ( all => [qw( gcm_encrypt_authenticate gcm_decrypt_verify )] );
our @EXPORT_OK = ( @{ $EXPORT_TAGS{'all'} } );
our @EXPORT = qw();
use Carp;
$Carp::Internal{(__PACKAGE__)}++;
use CryptX;
sub CLONE_SKIP { 1 } # prevent cloning
1;
=pod
=head1 NAME
Crypt::AuthEnc::GCM - Authenticated encryption in GCM mode
=head1 SYNOPSIS
### OO interface
use Crypt::AuthEnc::GCM;
# encrypt and authenticate
my $ae = Crypt::AuthEnc::GCM->new("AES", $key, $iv);
$ae->adata_add('additional_authenticated_data1');
$ae->adata_add('additional_authenticated_data2');
my $ct = $ae->encrypt_add('data1');
$ct .= $ae->encrypt_add('data2');
$ct .= $ae->encrypt_add('data3');
my $tag = $ae->encrypt_done();
# decrypt and verify
my $ae = Crypt::AuthEnc::GCM->new("AES", $key, $iv);
$ae->adata_add('additional_authenticated_data1');
$ae->adata_add('additional_authenticated_data2');
my $pt = $ae->decrypt_add('ciphertext1');
$pt .= $ae->decrypt_add('ciphertext2');
$pt .= $ae->decrypt_add('ciphertext3');
my $tag = $ae->decrypt_done();
die "decrypt failed" unless $tag eq $expected_tag;
#or
my $result = $ae->decrypt_done($expected_tag); # 0 or 1
### functional interface
use Crypt::AuthEnc::GCM qw(gcm_encrypt_authenticate gcm_decrypt_verify);
my ($ciphertext, $tag) = gcm_encrypt_authenticate('AES', $key, $iv, $adata, $plaintext);
my $plaintext = gcm_decrypt_verify('AES', $key, $iv, $adata, $ciphertext, $tag);
=head1 DESCRIPTION
Galois/Counter Mode (GCM) - provides encryption and authentication.
=head1 EXPORT
Nothing is exported by default.
You can export selected functions:
use Crypt::AuthEnc::GCM qw(gcm_encrypt_authenticate gcm_decrypt_verify);
=head1 FUNCTIONS
=head2 gcm_encrypt_authenticate
my ($ciphertext, $tag) = gcm_encrypt_authenticate($cipher, $key, $iv, $adata, $plaintext);
# $cipher .. 'AES' or name of any other cipher with 16-byte block len
# $key ..... AES key of proper length (128/192/256bits)
# $iv ...... initialization vector
# $adata ... additional authenticated data
=head2 gcm_decrypt_verify
my $plaintext = gcm_decrypt_verify($cipher, $key, $iv, $adata, $ciphertext, $tag);
# on error returns undef
=head1 METHODS
=head2 new
my $ae = Crypt::AuthEnc::GCM->new($cipher, $key);
#or
my $ae = Crypt::AuthEnc::GCM->new($cipher, $key, $iv);
# $cipher .. 'AES' or name of any other cipher
# $key ..... encryption key of proper length
# $iv ...... initialization vector (optional, you can set it later via iv_add method)
=head2 iv_add
Set initialization vector (IV).
$ae->iv_add($iv_data); #can be called multiple times
=head2 adata_add
Add B<additional authenticated data>.
Can be called B<after> all C<iv_add> calls but before the first C<encrypt_add> or C<decrypt_add>.
$ae->adata_add($aad_data); # can be called multiple times
=head2 encrypt_add
$ciphertext = $ae->encrypt_add($data); # can be called multiple times
=head2 encrypt_done
$tag = $ae->encrypt_done(); # returns $tag value
=head2 decrypt_add
$plaintext = $ae->decrypt_add($ciphertext); # can be called multiple times
=head2 decrypt_done
my $tag = $ae->decrypt_done; # returns $tag value
#or
my $result = $ae->decrypt_done($tag); # returns 1 (success) or 0 (failure)
=head2 reset
$ae->reset;
=head2 clone
my $ae_new = $ae->clone;
=head1 SEE ALSO
=over
=item * L<CryptX|CryptX>, L<Crypt::AuthEnc::CCM|Crypt::AuthEnc::CCM>, L<Crypt::AuthEnc::EAX|Crypt::AuthEnc::EAX>, L<Crypt::AuthEnc::OCB|Crypt::AuthEnc::OCB>
=item * L<https://en.wikipedia.org/wiki/Galois/Counter_Mode>
=back
=cut
|
