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   1  <?php
   2  
   3  /**
   4   * libsodium Key Handler
   5   *
   6   * Different NaCl implementations store the key differently.
   7   * https://blog.mozilla.org/warner/2011/11/29/ed25519-keys/ elaborates.
   8   * libsodium appears to use the same format as SUPERCOP.
   9   *
  10   * PHP version 5
  11   *
  12   * @category  Crypt
  13   * @package   EC
  14   * @author    Jim Wigginton <[email protected]>
  15   * @copyright 2015 Jim Wigginton
  16   * @license   http://www.opensource.org/licenses/mit-license.html  MIT License
  17   * @link      http://phpseclib.sourceforge.net
  18   */
  19  
  20  namespace phpseclib3\Crypt\EC\Formats\Keys;
  21  
  22  use phpseclib3\Crypt\EC\Curves\Ed25519;
  23  use phpseclib3\Exception\UnsupportedFormatException;
  24  use phpseclib3\Math\BigInteger;
  25  
  26  /**
  27   * libsodium Key Handler
  28   *
  29   * @package EC
  30   * @author  Jim Wigginton <[email protected]>
  31   * @access  public
  32   */
  33  abstract class libsodium
  34  {
  35      use Common;
  36  
  37      /**
  38       * Is invisible flag
  39       *
  40       * @access private
  41       */
  42      const IS_INVISIBLE = true;
  43  
  44      /**
  45       * Break a public or private key down into its constituent components
  46       *
  47       * @access public
  48       * @param string $key
  49       * @param string $password optional
  50       * @return array
  51       */
  52      public static function load($key, $password = '')
  53      {
  54          switch (strlen($key)) {
  55              case 32:
  56                  $public = $key;
  57                  break;
  58              case 64:
  59                  $private = substr($key, 0, 32);
  60                  $public = substr($key, -32);
  61                  break;
  62              case 96:
  63                  $public = substr($key, -32);
  64                  if (substr($key, 32, 32) != $public) {
  65                      throw new \RuntimeException('Keys with 96 bytes should have the 2nd and 3rd set of 32 bytes match');
  66                  }
  67                  $private = substr($key, 0, 32);
  68                  break;
  69              default:
  70                  throw new \RuntimeException('libsodium keys need to either be 32 bytes long, 64 bytes long or 96 bytes long');
  71          }
  72  
  73          $curve = new Ed25519();
  74          $components = ['curve' => $curve];
  75          if (isset($private)) {
  76              $components['dA'] = $curve->extractSecret($private);
  77          }
  78          $components['QA'] = isset($public) ?
  79              self::extractPoint($public, $curve) :
  80              $curve->multiplyPoint($curve->getBasePoint(), $components['dA']);
  81  
  82          return $components;
  83      }
  84  
  85      /**
  86       * Convert an EC public key to the appropriate format
  87       *
  88       * @access public
  89       * @param \phpseclib3\Crypt\EC\Curves\Ed25519 $curve
  90       * @param \phpseclib3\Math\Common\FiniteField\Integer[] $publicKey
  91       * @return string
  92       */
  93      public static function savePublicKey(Ed25519 $curve, array $publicKey)
  94      {
  95          return $curve->encodePoint($publicKey);
  96      }
  97  
  98      /**
  99       * Convert a private key to the appropriate format.
 100       *
 101       * @access public
 102       * @param \phpseclib3\Math\BigInteger $privateKey
 103       * @param \phpseclib3\Crypt\EC\Curves\Ed25519 $curve
 104       * @param \phpseclib3\Math\Common\FiniteField\Integer[] $publicKey
 105       * @param string $password optional
 106       * @return string
 107       */
 108      public static function savePrivateKey(BigInteger $privateKey, Ed25519 $curve, array $publicKey, $password = '')
 109      {
 110          if (!isset($privateKey->secret)) {
 111              throw new \RuntimeException('Private Key does not have a secret set');
 112          }
 113          if (strlen($privateKey->secret) != 32) {
 114              throw new \RuntimeException('Private Key secret is not of the correct length');
 115          }
 116          if (!empty($password) && is_string($password)) {
 117              throw new UnsupportedFormatException('libsodium private keys do not support encryption');
 118          }
 119          return $privateKey->secret . $curve->encodePoint($publicKey);
 120      }
 121  }