<?php

/**
 * SSH2 Signature Handler
 *
 * PHP version 5
 *
 * Handles signatures in the format used by SSH2
 *
 * @author    Jim Wigginton <terrafrost@php.net>
 * @copyright 2016 Jim Wigginton
 * @license   http://www.opensource.org/licenses/mit-license.html  MIT License
 * @link      http://phpseclib.sourceforge.net
 */
namespace ForminatorGoogleAddon\phpseclib3\Crypt\DSA\Formats\Signature;

use ForminatorGoogleAddon\phpseclib3\Common\Functions\Strings;
use ForminatorGoogleAddon\phpseclib3\Math\BigInteger;
/**
 * SSH2 Signature Handler
 *
 * @author  Jim Wigginton <terrafrost@php.net>
 */
abstract class SSH2
{
    /**
     * Loads a signature
     *
     * @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) = $result;
        if ($type != 'ssh-dss' || \strlen($blob) != 40) {
            return \false;
        }
        return ['r' => new BigInteger(\substr($blob, 0, 20), 256), 's' => new BigInteger(\substr($blob, 20), 256)];
    }
    /**
     * Returns a signature in the appropriate format
     *
     * @param BigInteger $r
     * @param BigInteger $s
     * @return string
     */
    public static function save(BigInteger $r, BigInteger $s)
    {
        if ($r->getLength() > 160 || $s->getLength() > 160) {
            return \false;
        }
        return Strings::packSSH2('ss', 'ssh-dss', \str_pad($r->toBytes(), 20, "\x00", \STR_PAD_LEFT) . \str_pad($s->toBytes(), 20, "\x00", \STR_PAD_LEFT));
    }
}