* @copyright 2016 Jim Wigginton * @license http://www.opensource.org/licenses/mit-license.html MIT License * @link http://phpseclib.sourceforge.net */ namespace phpseclib\Crypt\ECDSA\Signature; use phpseclib\Math\BigInteger; use phpseclib\Common\Functions\Strings; /** * SSH2 Signature Handler * * @package Common * @author Jim Wigginton * @access public */ abstract class SSH2 { /** * Loads a signature * * @access public * @param string $sig * @return mixed */ public static function load($sig) { if (!is_string($sig)) { return false; } $result = Strings::unpackSSH2('ss', $sig); if ($result === false) { return false; } list($type, $blob) = $result; switch ($type) { // see https://tools.ietf.org/html/rfc5656#section-3.1.2 case 'ecdsa-sha2-nistp256': case 'ecdsa-sha2-nistp384': case 'ecdsa-sha2-nistp521': break; default: return false; } $length = ceil(substr($type, 16) / 8); return [ 'r' => new BigInteger(substr($blob, 0, $length), 256), 's' => new BigInteger(substr($blob, $length), 256) ]; } /** * Returns a signature in the appropriate format * * @access public * @param \phpseclib\Math\BigInteger $r * @param \phpseclib\Math\BigInteger $s * @param string $curve * @return string */ public static function save(BigInteger $r, BigInteger $s, $curve) { switch ($curve) { case 'nistp256': case 'nistp384': case 'nistp521': break; default: return false; } $length = ceil(substr($curve, 5) / 8); return Strings::packSSH2('ss', 'ecdsa-sha2-' . $curve, str_pad($r->toBytes(), $length, "\0", STR_PAD_LEFT) . str_pad($s->toBytes(), $length, "\0", STR_PAD_LEFT) ); } }