RC4.php — JetBackup – Backup, Restore & Migrate 3.1.13.4

backup / src / JetBackup / 3rdparty / phpseclib3 / Crypt / RC4.php

backup / src / JetBackup / 3rdparty / phpseclib3 / Crypt Last commit date

Common 9 months ago DH 9 months ago DSA 9 months ago EC 9 months ago RSA 9 months ago .htaccess 9 months ago AES.php 9 months ago Blowfish.php 9 months ago ChaCha20.php 9 months ago DES.php 9 months ago DH.php 9 months ago DSA.php 9 months ago EC.php 9 months ago Hash.php 9 months ago PublicKeyLoader.php 9 months ago RC2.php 9 months ago RC4.php 9 months ago RSA.php 9 months ago Random.php 9 months ago Rijndael.php 9 months ago Salsa20.php 9 months ago TripleDES.php 9 months ago Twofish.php 9 months ago index.html 9 months ago web.config 9 months ago

RC4.php

265 lines

1	<?php
2
3	/**
4	* Pure-PHP implementation of RC4.
5	*
6	* Uses OpenSSL, if available/possible, and an internal implementation, otherwise
7	*
8	* PHP version 5
9	*
10	* Useful resources are as follows:
11	*
12	* - {@link http://www.mozilla.org/projects/security/pki/nss/draft-kaukonen-cipher-arcfour-03.txt ARCFOUR Algorithm}
13	* - {@link http://en.wikipedia.org/wiki/RC4 - Wikipedia: RC4}
14	*
15	* RC4 is also known as ARCFOUR or ARC4. The reason is elaborated upon at Wikipedia. This class is named RC4 and not
16	* ARCFOUR or ARC4 because RC4 is how it is referred to in the SSH1 specification.
17	*
18	* Here's a short example of how to use this library:
19	* <code>
20	* <?php
21	* include 'vendor/autoload.php';
22	*
23	* $rc4 = new \phpseclib3\Crypt\RC4();
24	*
25	* $rc4->setKey('abcdefgh');
26	*
27	* $size = 10 * 1024;
28	* $plaintext = '';
29	* for ($i = 0; $i < $size; $i++) {
30	* $plaintext.= 'a';
31	* }
32	*
33	* echo $rc4->decrypt($rc4->encrypt($plaintext));
34	* ?>
35	* </code>
36	*
37	* @author Jim Wigginton <terrafrost@php.net>
38	* @copyright 2007 Jim Wigginton
39	* @license http://www.opensource.org/licenses/mit-license.html MIT License
40	* @link http://phpseclib.sourceforge.net
41	*/
42
43	declare(strict_types=1);
44
45	namespace phpseclib3\Crypt;
46
47	use phpseclib3\Crypt\Common\StreamCipher;
48	use phpseclib3\Exception\LengthException;
49
50	/**
51	* Pure-PHP implementation of RC4.
52	*
53	* @author Jim Wigginton <terrafrost@php.net>
54	*/
55	class RC4 extends StreamCipher
56	{
57	/**
58	* @see \phpseclib3\Crypt\RC4::_crypt()
59	*/
60	public const ENCRYPT = 0;
61
62	/**
63	* @see \phpseclib3\Crypt\RC4::_crypt()
64	*/
65	public const DECRYPT = 1;
66
67	/**
68	* Key Length (in bytes)
69	*
70	* @see \phpseclib3\Crypt\RC4::setKeyLength()
71	* @var int
72	*/
73	protected $key_length = 128; // = 1024 bits
74
75	/**
76	* The Key
77	*
78	* @see self::setKey()
79	* @var string
80	*/
81	protected $key;
82
83	/**
84	* The Key Stream for decryption and encryption
85	*
86	* @see self::setKey()
87	* @var array
88	*/
89	private $stream;
90
91	/**
92	* Test for engine validity
93	*
94	* This is mainly just a wrapper to set things up for \phpseclib3\Crypt\Common\SymmetricKey::isValidEngine()
95	*
96	* @see \phpseclib3\Crypt\Common\SymmetricKey::__construct()
97	*/
98	protected function isValidEngineHelper(int $engine): bool
99	{
100	if ($engine == self::ENGINE_OPENSSL) {
101	if ($this->continuousBuffer) {
102	return false;
103	}
104	// quoting https://www.openssl.org/news/openssl-3.0-notes.html, OpenSSL 3.0.1
105	// "Moved all variations of the EVP ciphers CAST5, BF, IDEA, SEED, RC2, RC4, RC5, and DES to the legacy provider"
106	// in theory openssl_get_cipher_methods() should catch this but, on GitHub Actions, at least, it does not
107	if (defined('OPENSSL_VERSION_TEXT') && version_compare(preg_replace('#OpenSSL (\d+\.\d+\.\d+) .*#', '$1', OPENSSL_VERSION_TEXT), '3.0.1', '>=')) {
108	return false;
109	}
110	$this->cipher_name_openssl = 'rc4-40';
111	}
112
113	return parent::isValidEngineHelper($engine);
114	}
115
116	/**
117	* Sets the key length
118	*
119	* Keys can be between 1 and 256 bytes long.
120	*
121	* @throws LengthException if the key length is invalid
122	*/
123	public function setKeyLength(int $length): void
124	{
125	if ($length < 8 \|\| $length > 2048) {
126	throw new LengthException('Key size of ' . $length . ' bits is not supported by this algorithm. Only keys between 1 and 256 bytes are supported');
127	}
128
129	$this->key_length = $length >> 3;
130
131	parent::setKeyLength($length);
132	}
133
134	/**
135	* Sets the key length
136	*
137	* Keys can be between 1 and 256 bytes long.
138	*/
139	public function setKey(string $key): void
140	{
141	$length = strlen($key);
142	if ($length < 1 \|\| $length > 256) {
143	throw new LengthException('Key size of ' . $length . ' bytes is not supported by RC4. Keys must be between 1 and 256 bytes long');
144	}
145
146	parent::setKey($key);
147	}
148
149	/**
150	* Encrypts a message.
151	*
152	* @return string $ciphertext
153	* @see \phpseclib3\Crypt\Common\SymmetricKey::decrypt()
154	* @see self::crypt()
155	*/
156	public function encrypt(string $plaintext): string
157	{
158	if ($this->engine != self::ENGINE_INTERNAL) {
159	return parent::encrypt($plaintext);
160	}
161	return $this->crypt($plaintext, self::ENCRYPT);
162	}
163
164	/**
165	* Decrypts a message.
166	*
167	* $this->decrypt($this->encrypt($plaintext)) == $this->encrypt($this->encrypt($plaintext)).
168	* At least if the continuous buffer is disabled.
169	*
170	* @return string $plaintext
171	* @see \phpseclib3\Crypt\Common\SymmetricKey::encrypt()
172	* @see self::crypt()
173	*/
174	public function decrypt(string $ciphertext): string
175	{
176	if ($this->engine != self::ENGINE_INTERNAL) {
177	return parent::decrypt($ciphertext);
178	}
179	return $this->crypt($ciphertext, self::DECRYPT);
180	}
181
182	/**
183	* Encrypts a block
184	*/
185	protected function encryptBlock(string $in): string
186	{
187	// RC4 does not utilize this method
188	return '';
189	}
190
191	/**
192	* Decrypts a block
193	*/
194	protected function decryptBlock(string $in): string
195	{
196	// RC4 does not utilize this method
197	return '';
198	}
199
200	/**
201	* Setup the key (expansion)
202	*
203	* @see \phpseclib3\Crypt\Common\SymmetricKey::_setupKey()
204	*/
205	protected function setupKey(): void
206	{
207	$key = $this->key;
208	$keyLength = strlen($key);
209	$keyStream = range(0, 255);
210	$j = 0;
211	for ($i = 0; $i < 256; $i++) {
212	$j = ($j + $keyStream[$i] + ord($key[$i % $keyLength])) & 255;
213	$temp = $keyStream[$i];
214	$keyStream[$i] = $keyStream[$j];
215	$keyStream[$j] = $temp;
216	}
217
218	$this->stream = [];
219	$this->stream[self::DECRYPT] = $this->stream[self::ENCRYPT] = [
220	0, // index $i
221	0, // index $j
222	$keyStream,
223	];
224	}
225
226	/**
227	* Encrypts or decrypts a message.
228	*
229	* @return string $text
230	* @see self::decrypt()
231	* @see self::encrypt()
232	*/
233	private function crypt(string $text, int $mode): string
234	{
235	if ($this->changed) {
236	$this->setup();
237	}
238
239	$stream = &$this->stream[$mode];
240	if ($this->continuousBuffer) {
241	$i = &$stream[0];
242	$j = &$stream[1];
243	$keyStream = &$stream[2];
244	} else {
245	$i = $stream[0];
246	$j = $stream[1];
247	$keyStream = $stream[2];
248	}
249
250	$len = strlen($text);
251	for ($k = 0; $k < $len; ++$k) {
252	$i = ($i + 1) & 255;
253	$ksi = $keyStream[$i];
254	$j = ($j + $ksi) & 255;
255	$ksj = $keyStream[$j];
256
257	$keyStream[$i] = $ksj;
258	$keyStream[$j] = $ksi;
259	$text[$k] = $text[$k] ^ chr($keyStream[($ksj + $ksi) & 255]);
260	}
261
262	return $text;
263	}
264	}
265