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   1  <?php
   2  
   3  /**
   4   * PuTTY Formatted DSA Key Handler
   5   *
   6   * puttygen does not generate DSA keys with an N of anything other than 160, however,
   7   * it can still load them and convert them. PuTTY will load them, too, but SSH servers
   8   * won't accept them. Since PuTTY formatted keys are primarily used with SSH this makes
   9   * keys with N > 160 kinda useless, hence this handlers not supporting such keys.
  10   *
  11   * PHP version 5
  12   *
  13   * @category  Crypt
  14   * @package   DSA
  15   * @author    Jim Wigginton <[email protected]>
  16   * @copyright 2015 Jim Wigginton
  17   * @license   http://www.opensource.org/licenses/mit-license.html  MIT License
  18   * @link      http://phpseclib.sourceforge.net
  19   */
  20  
  21  namespace phpseclib3\Crypt\DSA\Formats\Keys;
  22  
  23  use phpseclib3\Common\Functions\Strings;
  24  use phpseclib3\Crypt\Common\Formats\Keys\PuTTY as Progenitor;
  25  use phpseclib3\Math\BigInteger;
  26  
  27  /**
  28   * PuTTY Formatted DSA Key Handler
  29   *
  30   * @package DSA
  31   * @author  Jim Wigginton <[email protected]>
  32   * @access  public
  33   */
  34  abstract class PuTTY extends Progenitor
  35  {
  36      /**
  37       * Public Handler
  38       *
  39       * @var string
  40       * @access private
  41       */
  42      const PUBLIC_HANDLER = 'phpseclib3\Crypt\DSA\Formats\Keys\OpenSSH';
  43  
  44      /**
  45       * Algorithm Identifier
  46       *
  47       * @var array
  48       * @access private
  49       */
  50      protected static $types = ['ssh-dss'];
  51  
  52      /**
  53       * Break a public or private key down into its constituent components
  54       *
  55       * @access public
  56       * @param string $key
  57       * @param string $password optional
  58       * @return array
  59       */
  60      public static function load($key, $password = '')
  61      {
  62          $components = parent::load($key, $password);
  63          if (!isset($components['private'])) {
  64              return $components;
  65          }
  66          extract($components);
  67          unset($components['public'], $components['private']);
  68  
  69          list($p, $q, $g, $y) = Strings::unpackSSH2('iiii', $public);
  70          list($x) = Strings::unpackSSH2('i', $private);
  71  
  72          return compact('p', 'q', 'g', 'y', 'x', 'comment');
  73      }
  74  
  75      /**
  76       * Convert a private key to the appropriate format.
  77       *
  78       * @access public
  79       * @param \phpseclib3\Math\BigInteger $p
  80       * @param \phpseclib3\Math\BigInteger $q
  81       * @param \phpseclib3\Math\BigInteger $g
  82       * @param \phpseclib3\Math\BigInteger $y
  83       * @param \phpseclib3\Math\BigInteger $x
  84       * @param string $password optional
  85       * @param array $options optional
  86       * @return string
  87       */
  88      public static function savePrivateKey(BigInteger $p, BigInteger $q, BigInteger $g, BigInteger $y, BigInteger $x, $password = false, array $options = [])
  89      {
  90          if ($q->getLength() != 160) {
  91              throw new \InvalidArgumentException('SSH only supports keys with an N (length of Group Order q) of 160');
  92          }
  93  
  94          $public = Strings::packSSH2('iiii', $p, $q, $g, $y);
  95          $private = Strings::packSSH2('i', $x);
  96  
  97          return self::wrapPrivateKey($public, $private, 'ssh-dsa', $password, $options);
  98      }
  99  
 100      /**
 101       * Convert a public key to the appropriate format
 102       *
 103       * @access public
 104       * @param \phpseclib3\Math\BigInteger $p
 105       * @param \phpseclib3\Math\BigInteger $q
 106       * @param \phpseclib3\Math\BigInteger $g
 107       * @param \phpseclib3\Math\BigInteger $y
 108       * @return string
 109       */
 110      public static function savePublicKey(BigInteger $p, BigInteger $q, BigInteger $g, BigInteger $y)
 111      {
 112          if ($q->getLength() != 160) {
 113              throw new \InvalidArgumentException('SSH only supports keys with an N (length of Group Order q) of 160');
 114          }
 115  
 116          return self::wrapPublicKey(Strings::packSSH2('iiii', $p, $q, $g, $y), 'ssh-dsa');
 117      }
 118  }