* @copyright 2015 Jim Wigginton * @license http://www.opensource.org/licenses/mit-license.html MIT License * @link http://phpseclib.sourceforge.net */ namespace phpseclib3\Crypt\DSA\Formats\Keys; use phpseclib3\Common\Functions\Strings; use phpseclib3\Exception\BadConfigurationException; use phpseclib3\Math\BigInteger; /** * XML Formatted DSA Key Handler * * @author Jim Wigginton */ abstract class XML { /** * Break a public or private key down into its constituent components * * @param string $key * @param string $password optional * @return array */ public static function load($key, $password = '') { if (!Strings::is_stringable($key)) { throw new \UnexpectedValueException('Key should be a string - not a ' . gettype($key)); } if (!class_exists('DOMDocument')) { throw new BadConfigurationException('The dom extension is not setup correctly on this system'); } $use_errors = libxml_use_internal_errors(true); $dom = new \DOMDocument(); if (substr($key, 0, 5) != '' . $key . ''; } if (!$dom->loadXML($key)) { libxml_use_internal_errors($use_errors); throw new \UnexpectedValueException('Key does not appear to contain XML'); } $xpath = new \DOMXPath($dom); $keys = ['p', 'q', 'g', 'y', 'j', 'seed', 'pgencounter']; foreach ($keys as $key) { // $dom->getElementsByTagName($key) is case-sensitive $temp = $xpath->query("//*[translate(local-name(), 'ABCDEFGHIJKLMNOPQRSTUVWXYZ','abcdefghijklmnopqrstuvwxyz')='$key']"); if (!$temp->length) { continue; } $value = new BigInteger(Strings::base64_decode($temp->item(0)->nodeValue), 256); switch ($key) { case 'p': // a prime modulus meeting the [DSS] requirements // Parameters P, Q, and G can be public and common to a group of users. They might be known // from application context. As such, they are optional but P and Q must either both appear // or both be absent $components['p'] = $value; break; case 'q': // an integer in the range 2**159 < Q < 2**160 which is a prime divisor of P-1 $components['q'] = $value; break; case 'g': // an integer with certain properties with respect to P and Q $components['g'] = $value; break; case 'y': // G**X mod P (where X is part of the private key and not made public) $components['y'] = $value; // the remaining options do not do anything case 'j': // (P - 1) / Q // Parameter J is available for inclusion solely for efficiency as it is calculatable from // P and Q case 'seed': // a DSA prime generation seed // Parameters seed and pgenCounter are used in the DSA prime number generation algorithm // specified in [DSS]. As such, they are optional but must either both be present or both // be absent case 'pgencounter': // a DSA prime generation counter } } libxml_use_internal_errors($use_errors); if (!isset($components['y'])) { throw new \UnexpectedValueException('Key is missing y component'); } switch (true) { case !isset($components['p']): case !isset($components['q']): case !isset($components['g']): return ['y' => $components['y']]; } return $components; } /** * Convert a public key to the appropriate format * * See https://www.w3.org/TR/xmldsig-core/#sec-DSAKeyValue * * @param \phpseclib3\Math\BigInteger $p * @param \phpseclib3\Math\BigInteger $q * @param \phpseclib3\Math\BigInteger $g * @param \phpseclib3\Math\BigInteger $y * @return string */ public static function savePublicKey(BigInteger $p, BigInteger $q, BigInteger $g, BigInteger $y) { return "\r\n" . '

' . Strings::base64_encode($p->toBytes()) . "

\r\n" . ' ' . Strings::base64_encode($q->toBytes()) . "\r\n" . ' ' . Strings::base64_encode($g->toBytes()) . "\r\n" . ' ' . Strings::base64_encode($y->toBytes()) . "\r\n" . ''; } }