CryptLib/Key/Derivation/PBKDF/SHA256.php

   1 <?php
   2 /**
   3  * An implementation of the crypt library's SHA512 hash method
   4  *
   5  * PHP version 5.3
   6  *
   7  * @category   PHPCryptLib
   8  * @package    Key
   9  * @subpackage Derivation
  10  * @author     Anthony Ferrara <ircmaxell@ircmaxell.com>
  11  * @copyright  2011 The Authors
  12  * @license    http://www.opensource.org/licenses/mit-license.html  MIT License
  13  * @version    Build @@version@@
  14  */
  15
  16 namespace CryptLib\Key\Derivation\PBKDF;
  17
  18 /**
  19  * An implementation of the crypt library's SHA512 hash method
  20  *
  21  * PHP version 5.3
  22  *
  23  * @category   PHPCryptLib
  24  * @package    Key
  25  * @subpackage Derivation
  26  * @author     Anthony Ferrara <ircmaxell@ircmaxell.com>
  27  */
  28 class SHA256
  29     extends \CryptLib\Key\Derivation\AbstractDerivation
  30     implements \CryptLib\Key\Derivation\PBKDF
  31 {
  32
  33     /**
  34      * Derive a key from the supplied arguments
  35      *
  36      * @param string $password   The password to derive from
  37      * @param string $salt       The salt string to use
  38      * @param int    $iterations The number of iterations to use
  39      * @param int    $length     The size of the string to generate
  40      *
  41      * @return string The derived key
  42      */
  43     public function derive($password, $salt, $iterations, $length) {
  44         $salt = substr(str_pad($salt, 16, chr(0)), 0, 16);
  45         $salt = '$5$rounds='.$iterations.'$'.$salt;
  46         return crypt($password, $salt);
  47     }
  48
  49     /**
  50      * Get the signature for this implementation
  51      *
  52      * This should include all information needed to build the same isntance
  53      * later.
  54      *
  55      * @return string The signature for this instance
  56      */
  57     public function getSignature() {
  58         return 'sha256';
  59     }
  60
  61 }
  62