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


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

SYNOPSIS
          use Crypt::Mode::OFB;
          my $m = Crypt::Mode::OFB->new('AES');

          #(en|de)crypt at once
          my $ciphertext = $m->encrypt($plaintext, $key, $iv);
          my $plaintext = $m->decrypt($ciphertext, $key, $iv);

          #encrypt more chunks
          $m->start_encrypt($key, $iv);
          my $ciphertext = $m->add('some data');
          $ciphertext .= $m->add('more data');

          #decrypt more chunks
          $m->start_decrypt($key, $iv);
          my $plaintext = $m->add($some_ciphertext);
          $plaintext .= $m->add($more_ciphertext);

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

METHODS
   new
        my $m = Crypt::Mode::OFB->new($name);
        #or
        my $m = Crypt::Mode::OFB->new($name, $cipher_rounds);

        # $name ............ one of 'AES', 'Anubis', 'Blowfish', 'CAST5', 'Camellia', 'DES', 'DES_EDE',
        #                    'KASUMI', 'Khazad', 'MULTI2', 'Noekeon', 'RC2', 'RC5', 'RC6',
        #                    'SAFERP', 'SAFER_K128', 'SAFER_K64', 'SAFER_SK128', 'SAFER_SK64',
        #                    'SEED', 'Skipjack', 'Twofish', 'XTEA', 'IDEA', 'Serpent'
        #                    simply any <NAME> for which there exists Crypt::Cipher::<NAME>
        # $cipher_rounds ... optional num of rounds for given cipher

   encrypt
          my $ciphertext = $m->encrypt($plaintext, $key, $iv);

   decrypt
          my $plaintext = $m->decrypt($ciphertext, $key, $iv);

   start_encrypt
          $m->start_encrypt($key, $iv);

   start_decrypt
          $m->start_decrypt($key, $iv);

   add
          # in encrypt mode
          my $plaintext = $m->add($ciphertext);

          # in decrypt mode
          my $ciphertext = $m->add($plaintext);

SEE ALSO
       o   CryptX, Crypt::Cipher

       o   Crypt::Cipher::AES, Crypt::Cipher::Blowfish, ...

       o   <https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation#Output_feedback_.28OFB.29>

perl v5.40.0                      2024-10-20               Crypt::Mode::OFB(3)