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📚 NAME

Crypt::Mode::CFB - Block cipher mode CFB [Cipher feedback]

🚀 Quick Reference

Use Case	Command	Description
Encrypt at once	$m->encrypt($plaintext, $key, $iv)	Encrypt entire plaintext in one call
Decrypt at once	$m->decrypt($ciphertext, $key, $iv)	Decrypt entire ciphertext in one call
Encrypt in chunks	$m->start_encrypt($key, $iv); $m->add('data');	Incremental encryption
Decrypt in chunks	$m->start_decrypt($key, $iv); $m->add($cipher);	Incremental decryption
Create mode object	Crypt::Mode::CFB->new('AES')	Initialize with cipher name

📖 SYNOPSIS

use 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($name, $cipher_rounds) — Create a new CFB mode object.

  my $m = Crypt::Mode::CFB->new($name);
  #or
  my $m = Crypt::Mode::CFB->new($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($plaintext, $key, $iv) — Encrypt plaintext.

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

• decrypt($ciphertext, $key, $iv) — Decrypt ciphertext.

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

• start_encrypt($key, $iv) — Initialize encryption stream.

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

• start_decrypt($key, $iv) — Initialize decryption stream.

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

• add($data) — Process data chunk (encrypt or decrypt).

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

📚 SEE ALSO

• CryptX, Crypt::Cipher
• Crypt::Cipher::AES, Crypt::Cipher::Blowfish, ...
• Wikipedia: Cipher feedback (CFB)

perl v5.34.0 2022-02-06 Crypt::Mode::CFB(3pm)

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