NAME

Crypt::Mode::CBC - Block cipher mode CBC [Cipher-block chaining]

SYNOPSIS

   Crypt::Mode::CBC;
   my $m = Crypt::Mode::CBC->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');
   $ciphertext .= $m->finish;

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

DESCRIPTION

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

METHODS

new

 my $m = Crypt::Mode::CBC->new('AES');
 #or
 my $m = Crypt::Mode::CBC->new('AES', $padding);
 #or
 my $m = Crypt::Mode::CBC->new('AES', $padding, $cipher_rounds);

 # $padding .... 0 no padding (plaintext size has to be myltiple of block length)
 #               1 PKCS5 padding, Crypt::CBC's "standard" - DEFAULT
 #               2 Crypt::CBC's "oneandzeroes"
 # $cipher_rounds ... optional num of rounds for given cipher
 

encrypt

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

decrypt

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

start_encrypt

start_decrypt

add

finish

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

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

SEE ALSO

CryptX