CryptLib/Key/Derivation/PBKDF/PBKDF1.php

   1 <?php
   2 /**
   3  * An implementation of the RFC 2898 PBKDF1 Standard key derivation function
   4  *
   5  * PHP version 5.3
   6  *
   7  * @see        http://www.ietf.org/rfc/rfc2898.txt
   8  * @category   PHPCryptLib
   9  * @package    Key
  10  * @subpackage Derivation
  11  * @author     Anthony Ferrara <ircmaxell@ircmaxell.com>
  12  * @copyright  2011 The Authors
  13  * @license    http://www.opensource.org/licenses/mit-license.html  MIT License
  14  * @version    Build @@version@@
  15  */
  16
  17 namespace CryptLib\Key\Derivation\PBKDF;
  18
  19 use CryptLib\Hash\Hash;
  20
  21 /**
  22  * An implementation of the RFC 2989 PBKDF1 Standard key derivation function
  23  *
  24  * @see        http://www.ietf.org/rfc/rfc2898.txt
  25  * @category   PHPCryptLib
  26  * @package    Key
  27  * @subpackage Derivation
  28  * @author     Anthony Ferrara <ircmaxell@ircmaxell.com>
  29  */
  30 class PBKDF1
  31     extends \CryptLib\Key\Derivation\AbstractDerivation
  32     implements \CryptLib\Key\Derivation\PBKDF
  33 {
  34
  35     /**
  36      * Derive a key from the supplied arguments
  37      *
  38      * @param string $password   The password to derive from
  39      * @param string $salt       The salt string to use
  40      * @param int    $iterations The number of iterations to use
  41      * @param int    $length     The size of the string to generate
  42      *
  43      * @return string The derived key
  44      */
  45     public function derive($password, $salt, $iterations, $length) {
  46         $size = Hash::getHashSize($this->hash);
  47         if ($length > $size) {
  48             $message = 'Length is too long for hash';
  49             throw new \InvalidArgumentException($message);
  50         }
  51         $tmp = hash($this->hash, $password . $salt, true);
  52         for ($i = 2; $i <= $iterations; $i++) {
  53             $tmp = hash($this->hash, $tmp, true);
  54         }
  55         return substr($tmp, 0, $length);
  56     }
  57
  58     /**
  59      * Get the signature for this implementation
  60      *
  61      * This should include all information needed to build the same isntance
  62      * later.
  63      *
  64      * @return string The signature for this instance
  65      */
  66     public function getSignature() {
  67         return 'pbkdf1-' . $this->hash;
  68     }
  69
  70 }
  71