1<?php
2
3/**
4 * Pure-PHP implementation of AES.
5 *
6 * Uses mcrypt, if available/possible, and an internal implementation, otherwise.
7 *
8 * PHP version 5
9 *
10 * NOTE: Since AES.php is (for compatibility and phpseclib-historical reasons) virtually
11 * just a wrapper to Rijndael.php you may consider using Rijndael.php instead of
12 * to save one include_once().
13 *
14 * If {@link self::setKeyLength() setKeyLength()} isn't called, it'll be calculated from
15 * {@link self::setKey() setKey()}.  ie. if the key is 128-bits, the key length will be 128-bits.  If it's 136-bits
16 * it'll be null-padded to 192-bits and 192 bits will be the key length until {@link self::setKey() setKey()}
17 * is called, again, at which point, it'll be recalculated.
18 *
19 * Since \phpseclib\Crypt\AES extends \phpseclib\Crypt\Rijndael, some functions are available to be called that, in the context of AES, don't
20 * make a whole lot of sense.  {@link self::setBlockLength() setBlockLength()}, for instance.  Calling that function,
21 * however possible, won't do anything (AES has a fixed block length whereas Rijndael has a variable one).
22 *
23 * Here's a short example of how to use this library:
24 * <code>
25 * <?php
26 *    include 'vendor/autoload.php';
27 *
28 *    $aes = new \phpseclib\Crypt\AES();
29 *
30 *    $aes->setKey('abcdefghijklmnop');
31 *
32 *    $size = 10 * 1024;
33 *    $plaintext = '';
34 *    for ($i = 0; $i < $size; $i++) {
35 *        $plaintext.= 'a';
36 *    }
37 *
38 *    echo $aes->decrypt($aes->encrypt($plaintext));
39 * ?>
40 * </code>
41 *
42 * @category  Crypt
43 * @package   AES
44 * @author    Jim Wigginton <terrafrost@php.net>
45 * @copyright 2008 Jim Wigginton
46 * @license   http://www.opensource.org/licenses/mit-license.html  MIT License
47 * @link      http://phpseclib.sourceforge.net
48 */
49
50namespace phpseclib\Crypt;
51
52/**
53 * Pure-PHP implementation of AES.
54 *
55 * @package AES
56 * @author  Jim Wigginton <terrafrost@php.net>
57 * @access  public
58 */
59class AES extends Rijndael
60{
61    /**
62     * Dummy function
63     *
64     * Since \phpseclib\Crypt\AES extends \phpseclib\Crypt\Rijndael, this function is, technically, available, but it doesn't do anything.
65     *
66     * @see \phpseclib\Crypt\Rijndael::setBlockLength()
67     * @access public
68     * @param int $length
69     */
70    function setBlockLength($length)
71    {
72        return;
73    }
74
75    /**
76     * Sets the key length
77     *
78     * Valid key lengths are 128, 192, and 256.  If the length is less than 128, it will be rounded up to
79     * 128.  If the length is greater than 128 and invalid, it will be rounded down to the closest valid amount.
80     *
81     * @see \phpseclib\Crypt\Rijndael:setKeyLength()
82     * @access public
83     * @param int $length
84     */
85    function setKeyLength($length)
86    {
87        switch ($length) {
88            case 160:
89                $length = 192;
90                break;
91            case 224:
92                $length = 256;
93        }
94        parent::setKeyLength($length);
95    }
96
97    /**
98     * Sets the key.
99     *
100     * Rijndael supports five different key lengths, AES only supports three.
101     *
102     * @see \phpseclib\Crypt\Rijndael:setKey()
103     * @see setKeyLength()
104     * @access public
105     * @param string $key
106     */
107    function setKey($key)
108    {
109        parent::setKey($key);
110
111        if (!$this->explicit_key_length) {
112            $length = strlen($key);
113            switch (true) {
114                case $length <= 16:
115                    $this->key_length = 16;
116                    break;
117                case $length <= 24:
118                    $this->key_length = 24;
119                    break;
120                default:
121                    $this->key_length = 32;
122            }
123            $this->_setEngine();
124        }
125    }
126}
127