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   1  <?php
   2  
   3  /**
   4   * Montgomery Private Key Handler
   5   *
   6   * "Naked" Curve25519 private keys can pretty much be any sequence of random 32x bytes so unless
   7   * we have a "hidden" key handler pretty much every 32 byte string will be loaded as a curve25519
   8   * private key even if it probably isn't one by PublicKeyLoader.
   9   *
  10   * "Naked" Curve25519 public keys also a string of 32 bytes so distinguishing between a "naked"
  11   * curve25519 private key and a public key is nigh impossible, hence separate plugins for each
  12   *
  13   * PHP version 5
  14   *
  15   * @author    Jim Wigginton <terrafrost@php.net>
  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\EC\Formats\Keys;
  22  
  23  use phpseclib3\Crypt\EC\BaseCurves\Montgomery as MontgomeryCurve;
  24  use phpseclib3\Crypt\EC\Curves\Curve25519;
  25  use phpseclib3\Crypt\EC\Curves\Curve448;
  26  use phpseclib3\Exception\UnsupportedFormatException;
  27  use phpseclib3\Math\BigInteger;
  28  
  29  /**
  30   * Montgomery Curve Private Key Handler
  31   *
  32   * @author  Jim Wigginton <terrafrost@php.net>
  33   */
  34  abstract class MontgomeryPrivate
  35  {
  36      /**
  37       * Is invisible flag
  38       *
  39       */
  40      const IS_INVISIBLE = true;
  41  
  42      /**
  43       * Break a public or private key down into its constituent components
  44       *
  45       * @param string $key
  46       * @param string $password optional
  47       * @return array
  48       */
  49      public static function load($key, $password = '')
  50      {
  51          switch (strlen($key)) {
  52              case 32:
  53                  $curve = new Curve25519();
  54                  break;
  55              case 56:
  56                  $curve = new Curve448();
  57                  break;
  58              default:
  59                  throw new \LengthException('The only supported lengths are 32 and 56');
  60          }
  61  
  62          $components = ['curve' => $curve];
  63          $components['dA'] = new BigInteger($key, 256);
  64          $curve->rangeCheck($components['dA']);
  65          // note that EC::getEncodedCoordinates does some additional "magic" (it does strrev on the result)
  66          $components['QA'] = $components['curve']->multiplyPoint($components['curve']->getBasePoint(), $components['dA']);
  67  
  68          return $components;
  69      }
  70  
  71      /**
  72       * Convert an EC public key to the appropriate format
  73       *
  74       * @param \phpseclib3\Crypt\EC\BaseCurves\Montgomery $curve
  75       * @param \phpseclib3\Math\Common\FiniteField\Integer[] $publicKey
  76       * @return string
  77       */
  78      public static function savePublicKey(MontgomeryCurve $curve, array $publicKey)
  79      {
  80          return strrev($publicKey[0]->toBytes());
  81      }
  82  
  83      /**
  84       * Convert a private key to the appropriate format.
  85       *
  86       * @param \phpseclib3\Math\BigInteger $privateKey
  87       * @param \phpseclib3\Crypt\EC\BaseCurves\Montgomery $curve
  88       * @param \phpseclib3\Math\Common\FiniteField\Integer[] $publicKey
  89       * @param string $secret optional
  90       * @param string $password optional
  91       * @return string
  92       */
  93      public static function savePrivateKey(BigInteger $privateKey, MontgomeryCurve $curve, array $publicKey, $secret = null, $password = '')
  94      {
  95          if (!empty($password) && is_string($password)) {
  96              throw new UnsupportedFormatException('MontgomeryPrivate private keys do not support encryption');
  97          }
  98  
  99          return $privateKey->toBytes();
 100      }
 101  }