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   1  <?php
   2  
   3  /**
   4   * XML Formatted RSA Key Handler
   5   *
   6   * More info:
   7   *
   8   * http://www.w3.org/TR/xmldsig-core/#sec-RSAKeyValue
   9   * http://www.w3.org/TR/xkms2/#XKMS_2_0_Paragraph_269
  10   * http://en.wikipedia.org/wiki/XML_Signature
  11   * http://en.wikipedia.org/wiki/XKMS
  12   *
  13   * PHP version 5
  14   *
  15   * @category  Crypt
  16   * @package   RSA
  17   * @author    Jim Wigginton <[email protected]>
  18   * @copyright 2015 Jim Wigginton
  19   * @license   http://www.opensource.org/licenses/mit-license.html  MIT License
  20   * @link      http://phpseclib.sourceforge.net
  21   */
  22  
  23  namespace phpseclib3\Crypt\RSA\Formats\Keys;
  24  
  25  use ParagonIE\ConstantTime\Base64;
  26  use phpseclib3\Common\Functions\Strings;
  27  use phpseclib3\Exception\BadConfigurationException;
  28  use phpseclib3\Exception\UnsupportedFormatException;
  29  use phpseclib3\Math\BigInteger;
  30  
  31  /**
  32   * XML Formatted RSA Key Handler
  33   *
  34   * @package RSA
  35   * @author  Jim Wigginton <[email protected]>
  36   * @access  public
  37   */
  38  abstract class XML
  39  {
  40      /**
  41       * Break a public or private key down into its constituent components
  42       *
  43       * @access public
  44       * @param string $key
  45       * @param string $password optional
  46       * @return array
  47       */
  48      public static function load($key, $password = '')
  49      {
  50          if (!Strings::is_stringable($key)) {
  51              throw new \UnexpectedValueException('Key should be a string - not a ' . gettype($key));
  52          }
  53  
  54          if (!class_exists('DOMDocument')) {
  55              throw new BadConfigurationException('The dom extension is not setup correctly on this system');
  56          }
  57  
  58          $components = [
  59              'isPublicKey' => false,
  60              'primes' => [],
  61              'exponents' => [],
  62              'coefficients' => []
  63          ];
  64  
  65          $use_errors = libxml_use_internal_errors(true);
  66  
  67          $dom = new \DOMDocument();
  68          if (substr($key, 0, 5) != '<?xml') {
  69              $key = '<xml>' . $key . '</xml>';
  70          }
  71          if (!$dom->loadXML($key)) {
  72              libxml_use_internal_errors($use_errors);
  73              throw new \UnexpectedValueException('Key does not appear to contain XML');
  74          }
  75          $xpath = new \DOMXPath($dom);
  76          $keys = ['modulus', 'exponent', 'p', 'q', 'dp', 'dq', 'inverseq', 'd'];
  77          foreach ($keys as $key) {
  78              // $dom->getElementsByTagName($key) is case-sensitive
  79              $temp = $xpath->query("//*[translate(local-name(), 'ABCDEFGHIJKLMNOPQRSTUVWXYZ','abcdefghijklmnopqrstuvwxyz')='$key']");
  80              if (!$temp->length) {
  81                  continue;
  82              }
  83              $value = new BigInteger(Base64::decode($temp->item(0)->nodeValue), 256);
  84              switch ($key) {
  85                  case 'modulus':
  86                      $components['modulus'] = $value;
  87                      break;
  88                  case 'exponent':
  89                      $components['publicExponent'] = $value;
  90                      break;
  91                  case 'p':
  92                      $components['primes'][1] = $value;
  93                      break;
  94                  case 'q':
  95                      $components['primes'][2] = $value;
  96                      break;
  97                  case 'dp':
  98                      $components['exponents'][1] = $value;
  99                      break;
 100                  case 'dq':
 101                      $components['exponents'][2] = $value;
 102                      break;
 103                  case 'inverseq':
 104                      $components['coefficients'][2] = $value;
 105                      break;
 106                  case 'd':
 107                      $components['privateExponent'] = $value;
 108              }
 109          }
 110  
 111          libxml_use_internal_errors($use_errors);
 112  
 113          foreach ($components as $key => $value) {
 114              if (is_array($value) && !count($value)) {
 115                  unset($components[$key]);
 116              }
 117          }
 118  
 119          if (isset($components['modulus']) && isset($components['publicExponent'])) {
 120              if (count($components) == 3) {
 121                  $components['isPublicKey'] = true;
 122              }
 123              return $components;
 124          }
 125  
 126          throw new \UnexpectedValueException('Modulus / exponent not present');
 127      }
 128  
 129      /**
 130       * Convert a private key to the appropriate format.
 131       *
 132       * @access public
 133       * @param \phpseclib3\Math\BigInteger $n
 134       * @param \phpseclib3\Math\BigInteger $e
 135       * @param \phpseclib3\Math\BigInteger $d
 136       * @param array $primes
 137       * @param array $exponents
 138       * @param array $coefficients
 139       * @param string $password optional
 140       * @return string
 141       */
 142      public static function savePrivateKey(BigInteger $n, BigInteger $e, BigInteger $d, array $primes, array $exponents, array $coefficients, $password = '')
 143      {
 144          if (count($primes) != 2) {
 145              throw new \InvalidArgumentException('XML does not support multi-prime RSA keys');
 146          }
 147  
 148          if (!empty($password) && is_string($password)) {
 149              throw new UnsupportedFormatException('XML private keys do not support encryption');
 150          }
 151  
 152          return "<RSAKeyPair>\r\n" .
 153                 '  <Modulus>' . Base64::encode($n->toBytes()) . "</Modulus>\r\n" .
 154                 '  <Exponent>' . Base64::encode($e->toBytes()) . "</Exponent>\r\n" .
 155                 '  <P>' . Base64::encode($primes[1]->toBytes()) . "</P>\r\n" .
 156                 '  <Q>' . Base64::encode($primes[2]->toBytes()) . "</Q>\r\n" .
 157                 '  <DP>' . Base64::encode($exponents[1]->toBytes()) . "</DP>\r\n" .
 158                 '  <DQ>' . Base64::encode($exponents[2]->toBytes()) . "</DQ>\r\n" .
 159                 '  <InverseQ>' . Base64::encode($coefficients[2]->toBytes()) . "</InverseQ>\r\n" .
 160                 '  <D>' . Base64::encode($d->toBytes()) . "</D>\r\n" .
 161                 '</RSAKeyPair>';
 162      }
 163  
 164      /**
 165       * Convert a public key to the appropriate format
 166       *
 167       * @access public
 168       * @param \phpseclib3\Math\BigInteger $n
 169       * @param \phpseclib3\Math\BigInteger $e
 170       * @return string
 171       */
 172      public static function savePublicKey(BigInteger $n, BigInteger $e)
 173      {
 174          return "<RSAKeyValue>\r\n" .
 175                 '  <Modulus>' . Base64::encode($n->toBytes()) . "</Modulus>\r\n" .
 176                 '  <Exponent>' . Base64::encode($e->toBytes()) . "</Exponent>\r\n" .
 177                 '</RSAKeyValue>';
 178      }
 179  }