Crypt::AuthEnc::OCB(3pm)

1Crypt::AuthEnc::OCB(3)User Contributed Perl DocumentationCrypt::AuthEnc::OCB(3)
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NAME

6       Crypt::AuthEnc::OCB - Authenticated encryption in OCBv3 mode
7

SYNOPSIS

9        ### OO interface
10        use Crypt::AuthEnc::OCB;
11
12        # encrypt and authenticate
13        my $ae = Crypt::AuthEnc::OCB->new("AES", $key, $nonce, $tag_len);
14        $ae->adata_add('additional_authenticated_data1');
15        $ae->adata_add('additional_authenticated_data2');
16        my $ct = $ae->encrypt_add('data1');
17        $ct .= $ae->encrypt_add('data2');
18        $ct .= $ae->encrypt_add('data3');
19        $ct .= $ae->encrypt_last('rest of data');
20        my $tag = $ae->encrypt_done();
21
22        # decrypt and verify
23        my $ae = Crypt::AuthEnc::OCB->new("AES", $key, $nonce, $tag_len);
24        $ae->adata_add('additional_authenticated_data1');
25        $ae->adata_add('additional_authenticated_data2');
26        my $pt = $ae->decrypt_add('ciphertext1');
27        $pt .= $ae->decrypt_add('ciphertext2');
28        $pt .= $ae->decrypt_add('ciphertext3');
29        $pt .= $ae->decrypt_last('rest of data');
30        my $tag = $ae->decrypt_done();
31        die "decrypt failed" unless $tag eq $expected_tag;
32
33        #or
34        my $result = $ae->decrypt_done($expected_tag); # 0 or 1
35
36        ### functional interface
37        use Crypt::AuthEnc::OCB qw(ocb_encrypt_authenticate ocb_decrypt_verify);
38
39        my ($ciphertext, $tag) = ocb_encrypt_authenticate('AES', $key, $nonce, $adata, $tag_len, $plaintext);
40        my $plaintext = ocb_decrypt_verify('AES', $key, $nonce, $adata, $ciphertext, $tag);
41

DESCRIPTION

43       This module implements OCB v3 according to
44       <https://tools.ietf.org/html/rfc7253>
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EXPORT

47       Nothing is exported by default.
48
49       You can export selected functions:
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51         use Crypt::AuthEnc::OCB qw(ocb_encrypt_authenticate ocb_decrypt_verify);
52

FUNCTIONS

54   ocb_encrypt_authenticate
55        my ($ciphertext, $tag) = ocb_encrypt_authenticate($cipher, $key, $nonce, $adata, $tag_len, $plaintext);
56
57        # $cipher .. 'AES' or name of any other cipher with 16-byte block len
58        # $key ..... AES key of proper length (128/192/256bits)
59        # $nonce ... unique nonce/salt (no need to keep it secret)
60        # $adata ... additional authenticated data
61        # $tag_len . required length of output tag
62
63   ocb_decrypt_verify
64         my $plaintext = ocb_decrypt_verify($cipher, $key, $nonce, $adata, $ciphertext, $tag);
65         # on error returns undef
66

METHODS

68   new
69        my $ae = Crypt::AuthEnc::OCB->new($cipher, $key, $nonce, $tag_len);
70
71        # $cipher .. 'AES' or name of any other cipher with 16-byte block len
72        # $key ..... AES key of proper length (128/192/256bits)
73        # $nonce ... unique nonce/salt (no need to keep it secret)
74        # $tag_len . required length of output tag
75
76   adata_add
77        $ae->adata_add($adata);                        #can be called multiple times
78
79   encrypt_add
80        $ciphertext = $ae->encrypt_add($data);         # can be called multiple times
81
82        #BEWARE: size of $data has to be multiple of blocklen (16 for AES)
83
84   encrypt_last
85        $ciphertext = $ae->encrypt_last($data);
86
87   encrypt_done
88        $tag = $ae->encrypt_done();                    # returns $tag value
89
90   decrypt_add
91        $plaintext = $ae->decrypt_add($ciphertext);    # can be called multiple times
92
93        #BEWARE: size of $ciphertext has to be multiple of blocklen (16 for AES)
94
95   decrypt_last
96        $plaintext = $ae->decrypt_last($data);
97
98   decrypt_done
99        my $tag = $ae->decrypt_done;           # returns $tag value
100        #or
101        my $result = $ae->decrypt_done($tag);  # returns 1 (success) or 0 (failure)
102
103   clone
104        my $ae_new = $ae->clone;
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NAME

SYNOPSIS

DESCRIPTION

EXPORT

FUNCTIONS

METHODS

SEE ALSO