1<?php
2
3/**
4 * PuTTY Formatted DSA Key Handler
5 *
6 * puttygen does not generate DSA keys with an N of anything other than 160, however,
7 * it can still load them and convert them. PuTTY will load them, too, but SSH servers
8 * won't accept them. Since PuTTY formatted keys are primarily used with SSH this makes
9 * keys with N > 160 kinda useless, hence this handlers not supporting such keys.
10 *
11 * PHP version 5
12 *
13 * @category  Crypt
14 * @package   DSA
15 * @author    Jim Wigginton <terrafrost@php.net>
16 * @copyright 2015 Jim Wigginton
17 * @license   http://www.opensource.org/licenses/mit-license.html  MIT License
18 * @link      http://phpseclib.sourceforge.net
19 */
20
21namespace phpseclib3\Crypt\DSA\Formats\Keys;
22
23use phpseclib3\Common\Functions\Strings;
24use phpseclib3\Crypt\Common\Formats\Keys\PuTTY as Progenitor;
25use phpseclib3\Math\BigInteger;
26
27/**
28 * PuTTY Formatted DSA Key Handler
29 *
30 * @package DSA
31 * @author  Jim Wigginton <terrafrost@php.net>
32 * @access  public
33 */
34abstract class PuTTY extends Progenitor
35{
36    /**
37     * Public Handler
38     *
39     * @var string
40     * @access private
41     */
42    const PUBLIC_HANDLER = 'phpseclib3\Crypt\DSA\Formats\Keys\OpenSSH';
43
44    /**
45     * Algorithm Identifier
46     *
47     * @var array
48     * @access private
49     */
50    protected static $types = ['ssh-dss'];
51
52    /**
53     * Break a public or private key down into its constituent components
54     *
55     * @access public
56     * @param string $key
57     * @param string $password optional
58     * @return array
59     */
60    public static function load($key, $password = '')
61    {
62        $components = parent::load($key, $password);
63        if (!isset($components['private'])) {
64            return $components;
65        }
66        extract($components);
67        unset($components['public'], $components['private']);
68
69        list($p, $q, $g, $y) = Strings::unpackSSH2('iiii', $public);
70        list($x) = Strings::unpackSSH2('i', $private);
71
72        return compact('p', 'q', 'g', 'y', 'x', 'comment');
73    }
74
75    /**
76     * Convert a private key to the appropriate format.
77     *
78     * @access public
79     * @param \phpseclib3\Math\BigInteger $p
80     * @param \phpseclib3\Math\BigInteger $q
81     * @param \phpseclib3\Math\BigInteger $g
82     * @param \phpseclib3\Math\BigInteger $y
83     * @param \phpseclib3\Math\BigInteger $x
84     * @param string $password optional
85     * @param array $options optional
86     * @return string
87     */
88    public static function savePrivateKey(BigInteger $p, BigInteger $q, BigInteger $g, BigInteger $y, BigInteger $x, $password = false, array $options = [])
89    {
90        if ($q->getLength() != 160) {
91            throw new \InvalidArgumentException('SSH only supports keys with an N (length of Group Order q) of 160');
92        }
93
94        $public = Strings::packSSH2('iiii', $p, $q, $g, $y);
95        $private = Strings::packSSH2('i', $x);
96
97        return self::wrapPrivateKey($public, $private, 'ssh-dsa', $password, $options);
98    }
99
100    /**
101     * Convert a public key to the appropriate format
102     *
103     * @access public
104     * @param \phpseclib3\Math\BigInteger $p
105     * @param \phpseclib3\Math\BigInteger $q
106     * @param \phpseclib3\Math\BigInteger $g
107     * @param \phpseclib3\Math\BigInteger $y
108     * @return string
109     */
110    public static function savePublicKey(BigInteger $p, BigInteger $q, BigInteger $g, BigInteger $y)
111    {
112        if ($q->getLength() != 160) {
113            throw new \InvalidArgumentException('SSH only supports keys with an N (length of Group Order q) of 160');
114        }
115
116        return self::wrapPublicKey(Strings::packSSH2('iiii', $p, $q, $g, $y), 'ssh-dsa');
117    }
118}
119