NAME
Crypt::Mode::CBC - Block cipher mode CBC [Cipher-block chaining]
SYNOPSIS
use 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 cipherencrypt
my $ciphertext = $m->encrypt($plaintext, $key, $iv);decrypt
my $plaintext = $m->decrypt($ciphertext, $key, $iv);start_encrypt
See example below "finish".
start_decrypt
See example below "finish".
add
See example below "finish".
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;