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📛 NAME

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

🚀 Quick Reference

Use Case	Command	Description
Instant encrypt	$m->encrypt($plaintext, $key, $iv)	Encrypt all at once
Instant decrypt	$m->decrypt($ciphertext, $key, $iv)	Decrypt all at once
Chunked encrypt	$m->start_encrypt($key, $iv); $m->add(...); $m->finish	Encrypt stream in parts
Chunked decrypt	$m->start_decrypt($key, $iv); $m->add(...); $m->finish	Decrypt stream in parts
Set padding	Crypt::Mode::CBC->new('AES', 1)	PKCS5 padding (default)
No padding	Crypt::Mode::CBC->new('AES', 0)	Plaintext must be multiple of block size
Custom rounds	Crypt::Mode::CBC->new('AES', 1, 12)	Specify cipher rounds

📋 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 $m = Crypt::Mode::CBC->new($name);
#or
my $m = Crypt::Mode::CBC->new($name, $padding);
#or
my $m = Crypt::Mode::CBC->new($name, $padding, $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>
# $padding .... 0 no padding (plaintext size has to be multiple of block length)
#               1 PKCS5 padding, Crypt::CBC's "standard" - DEFAULT
#               2 Crypt::CBC's "oneandzeroes"
#               3 ANSI X.923 padding
#               4 zero padding
#               5 zero padding (+a block of zeros if the output length is divisible by the blocksize)
# $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);

🏁 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, Crypt::Cipher
• Crypt::Cipher::AES, Crypt::Cipher::Blowfish, ...
• <https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation#Cipher-block_chaining_.28CBC.29>

📛 NAME 🚀 Quick Reference 📋 SYNOPSIS 📖 DESCRIPTION 🔧 METHODS 📚 SEE ALSO