1Crypt::Mode::OFB(3)   User Contributed Perl Documentation  Crypt::Mode::OFB(3)
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NAME

6       Crypt::Mode::OFB - Block cipher mode OFB [Output feedback]
7

SYNOPSIS

9          use Crypt::Mode::OFB;
10          my $m = Crypt::Mode::OFB->new('AES');
11
12          #(en|de)crypt at once
13          my $ciphertext = $m->encrypt($plaintext, $key, $iv);
14          my $plaintext = $m->decrypt($ciphertext, $key, $iv);
15
16          #encrypt more chunks
17          $m->start_encrypt($key, $iv);
18          my $ciphertext = $m->add('some data');
19          $ciphertext .= $m->add('more data');
20
21          #decrypt more chunks
22          $m->start_decrypt($key, $iv);
23          my $plaintext = $m->add($some_ciphertext);
24          $plaintext .= $m->add($more_ciphertext);
25

DESCRIPTION

27       This module implements OFB cipher mode. NOTE: it works only with
28       ciphers from CryptX (Crypt::Cipher::NNNN).
29

METHODS

31   new
32        my $m = Crypt::Mode::OFB->new('AES');
33        #or
34        my $m = Crypt::Mode::OFB->new('AES', $cipher_rounds);
35
36        # $cipher_rounds ... optional num of rounds for given cipher
37
38   encrypt
39          my $ciphertext = $m->encrypt($plaintext, $key, $iv);
40
41   decrypt
42          my $plaintext = $m->decrypt($ciphertext, $key, $iv);
43
44   start_encrypt
45          $m->start_encrypt($key, $iv);
46
47   start_decrypt
48          $m->start_decrypt($key, $iv);
49
50   add
51          # in encrypt mode
52          my $plaintext = $m->add($ciphertext);
53
54          # in decrypt mode
55          my $ciphertext = $m->add($plaintext);
56

SEE ALSO

58       ·   CryptX, Crypt::Cipher
59
60       ·   Crypt::Cipher::AES, Crypt::Cipher::Blowfish, ...
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62       ·   <https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation#Output_feedback_.28OFB.29>
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66perl v5.32.1                      2021-03-30               Crypt::Mode::OFB(3)
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