# phpman > perldoc > Crypt::Cipher

## NAME
    [Crypt::Cipher](https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3ACipher/markdown) - Generic interface to cipher functions

## SYNOPSIS
       #### example 1 (encrypting single block)
       use [Crypt::Cipher](https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3ACipher/markdown);

       my $key = '...'; # length has to be valid key size for this cipher
       my $c = [Crypt::Cipher](https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3ACipher/markdown)->new('AES', $key);
       my $blocksize  = $c->blocksize;
       my $ciphertext = $c->encrypt('plain text block'); #encrypt 1 block
       my $plaintext  = $c->decrypt($ciphertext);         #decrypt 1 block

       ### example 2 (using CBC mode)
       use [Crypt::Mode::CBC](https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3AMode%3A%3ACBC/markdown);

       my $key = '...'; # length has to be valid key size for this cipher
       my $iv = '...';  # 16 bytes
       my $cbc = [Crypt::Mode::CBC](https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3AMode%3A%3ACBC/markdown)->new('AES');
       my $ciphertext = $cbc->encrypt("secret data", $key, $iv);

       #### example 3 (compatibility with [Crypt::CBC](https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3ACBC/markdown))
       use [Crypt::CBC](https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3ACBC/markdown);
       use [Crypt::Cipher](https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3ACipher/markdown);

       my $key = '...'; # length has to be valid key size for this cipher
       my $iv = '...';  # 16 bytes
       my $cipher = [Crypt::Cipher](https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3ACipher/markdown)('AES', $key);
       my $cbc = [Crypt::CBC](https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3ACBC/markdown)->new( -cipher=>$cipher, -iv=>$iv );
       my $ciphertext = $cbc->encrypt("secret data");

## DESCRIPTION
    Provides an interface to various symmetric cipher algorithms.

    BEWARE: This module implements just elementary "one-block-(en|de)cryption" operation - if you
    want to encrypt/decrypt generic data you have to use some of the cipher block modes - check for
    example [Crypt::Mode::CBC](https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3AMode%3A%3ACBC/markdown), [Crypt::Mode::CTR](https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3AMode%3A%3ACTR/markdown) or [Crypt::CBC](https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3ACBC/markdown) (which will be slower).

## METHODS
  new
    Constructor, returns a reference to the cipher object.

     ## basic scenario
     $d = [Crypt::Cipher](https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3ACipher/markdown)->new($name, $key);
     # $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](https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3ACipher/markdown)::<NAME>
     # $key = binary key (keysize should comply with selected cipher requirements)

     ## some of the ciphers (e.g. MULTI2, RC5, SAFER) allow one to set number of rounds
     $d = [Crypt::Cipher](https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3ACipher/markdown)->new('MULTI2', $key, $rounds);
     # $rounds = positive integer (should comply with selected cipher requirements)

  encrypt
    Encrypts $plaintext and returns the $ciphertext where $plaintext and $ciphertext should be of
    blocksize bytes.

     $ciphertext = $d->encrypt($plaintext);

  decrypt
    Decrypts $ciphertext and returns the $plaintext where $plaintext and $ciphertext should be of
    blocksize bytes.

     $plaintext = $d->decrypt($ciphertext);

  keysize
    Just an alias for max_keysize (needed for [Crypt::CBC](https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3ACBC/markdown) compatibility).

  max_keysize
    Returns the maximal allowed key size (in bytes) for given cipher.

     $d->max_keysize;
     #or
     [Crypt::Cipher](https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3ACipher/markdown)->max_keysize('AES');
     #or
     [Crypt::Cipher::max_keysize](https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3ACipher%3A%3Amaxkeysize/markdown)('AES');

  min_keysize
    Returns the minimal allowed key size (in bytes) for given cipher.

     $d->min_keysize;
     #or
     [Crypt::Cipher](https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3ACipher/markdown)->min_keysize('AES');
     #or
     [Crypt::Cipher::min_keysize](https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3ACipher%3A%3Aminkeysize/markdown)('AES');

  blocksize
    Returns block size (in bytes) for given cipher.

     $d->blocksize;
     #or
     [Crypt::Cipher](https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3ACipher/markdown)->blocksize('AES');
     #or
     [Crypt::Cipher::blocksize](https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3ACipher%3A%3Ablocksize/markdown)('AES');

  default_rounds
    Returns default number of rounds for given cipher. NOTE: only some ciphers (e.g. MULTI2, RC5,
    SAFER) allow one to set number of rounds via new().

     $d->default_rounds;
     #or
     [Crypt::Cipher](https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3ACipher/markdown)->default_rounds('AES');
     #or
     [Crypt::Cipher::default_rounds](https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3ACipher%3A%3Adefaultrounds/markdown)('AES');

## SEE ALSO
    *   CryptX

    *   Check subclasses like [Crypt::Cipher::AES](https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3ACipher%3A%3AAES/markdown), [Crypt::Cipher::Blowfish](https://www.chedong.com/phpMan.php/perldoc/Crypt%3A%3ACipher%3A%3ABlowfish/markdown), ...