NAME
Crypt::Mode::CFB - Block cipher mode CFB [Cipher feedback]
SYNOPSIS
Crypt::Mode::CFB;
my $m = Crypt::Mode::CFB->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 CFB cipher mode. NOTE: it works only with ciphers from CryptX (Crypt::Cipher::NNNN).
METHODS
new
my $m = Crypt::Mode::CFB->new('AES');
#or
my $m = Crypt::Mode::CFB->new('AES', $cipher_rounds);
# $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');
#decrypt more chunks
$m->start_decrypt($key, $iv);
my $plaintext = '';
$plaintext .= $m->add($some_ciphertext);
$plaintext .= $m->add($more_ciphertext);