s2member / src / includes / classes / utils-encryption.inc.php

utils-encryption.inc.php in s2Member – Excellent for All Kinds of Memberships, Content Restriction Paywalls & Member Access Subscriptions trunk, at src/includes/classes/utils-encryption.inc.php

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1	<?php
2	// @codingStandardsIgnoreFile
3	/**
4	* Encryption utilities.
5	*
6	* @since 3.5 Nearly the first release.
7	*/
8	if (!defined('WPINC')) { // MUST have.
9	exit('Do not access this file directly.');
10	}
11	if (!class_exists('c_ws_plugin__s2member_utils_encryption')) {
12	/**
13	* Encryption utilities.
14	*
15	* @since 3.5 Nearly the first release.
16	*/
17	class c_ws_plugin__s2member_utils_encryption
18	{
19	/**
20	* Encryption key.
21	*
22	* @since 111106 Get key.
23	*
24	* @param string $key Custom key.
25	*
26	* @return string Encryption key.
27	*/
28	public static function key($key = '')
29	{
30	if (($key = trim((string) $key))) {
31	return $key;
32	} elseif (($key = $GLOBALS['WS_PLUGIN__']['s2member']['o']['sec_encryption_key'])) {
33	return $key;
34	} elseif (($key = wp_salt())) {
35	return $key;
36	}
37	return $key = md5($_SERVER['HTTP_HOST']);
38	}
39
40	/**
41	* A unique, unguessable, non-numeric, caSe-insensitive key (20 chars max).
42	*
43	* @since 150124 Adding gift code generation.
44	*
45	* @note 32-bit systems usually have `PHP_INT_MAX` = `2147483647`.
46	* We limit `mt_rand()` to a max of `999999999`.
47	*
48	* @note A max possible length of 20 chars assumes this function
49	* will not be called after `Sat, 20 Nov 2286 17:46:39 GMT`.
50	* At which point a UNIX timestamp will grow in size.
51	*
52	* @note Key always begins with a `k` to prevent PHP's `is_numeric()`
53	* function from ever thinking it's a number in a different representation.
54	* See: <http://php.net/manual/en/function.is-numeric.php> for further details.
55	*
56	* @return string A unique, unguessable, non-numeric, caSe-insensitive key (20 chars max).
57	*/
58	public static function uunnci_key_20_max()
59	{
60	$microtime_19_max = number_format(microtime(true), 9, '.', '');
61	// e.g., `9999999999`.`999999999` (max decimals: `9`, max overall precision: `19`).
62	// Assuming timestamp is never > 10 digits; i.e., before `Sat, 20 Nov 2286 17:46:39 GMT`.
63
64	list($seconds_10_max, $microseconds_9_max) = explode('.', $microtime_19_max, 2);
65	// e.g., `array(`9999999999`, `999999999`)`. Max total digits combined: `19`.
66
67	$seconds_base36 = base_convert($seconds_10_max, '10', '36'); // e.g., max `9999999999`, to base 36.
68	$microseconds_base36 = base_convert($microseconds_9_max, '10', '36'); // e.g., max `999999999`, to base 36.
69	$mt_rand_base36 = base_convert(mt_rand(1, 999999999), '10', '36'); // e.g., max `999999999`, to base 36.
70	$key = 'k'.$mt_rand_base36.$seconds_base36.$microseconds_base36; // e.g., `kgjdgxr4ldqpdrgjdgxr`.
71
72	return $key; // Max possible value: `kgjdgxr4ldqpdrgjdgxr` (20 chars).
73	}
74
75	/**
76	* Encrypt w/ best possible technique.
77	*
78	* @since 3.5 Nearly the first release.
79	*
80	* @param string $string String to encrypt.
81	* @param string $key Optional custom encryption key.
82	* @param bool $w_md5_cs Defaults to true. When true, an MD5 checksum.
83	* @param bool\|null $allow_defuse Allow Defuse encryption as a better alternative?
84	*
85	* @return string Encrypted string.
86	*/
87	public static function encrypt($string = '', $key = '', $w_md5_cs = true, $allow_defuse = null)
88	{
89	$allow_defuse = isset($allow_defuse) ? $allow_defuse
90	: apply_filters('c_ws_plugin__s2member_allow_defuse', true);
91
92	if ($allow_defuse && version_compare(PHP_VERSION, '7.0.4', '>=')) {
93	return c_ws_plugin__s2member_utils_defuse::encrypt($string, $key);
94	} // This is a new/improved way of handling encryption.
95
96	if (function_exists('mcrypt_encrypt')
97	&& in_array('rijndael-256', @mcrypt_list_algorithms())
98	&& in_array('cbc', @mcrypt_list_modes())) {
99	//
100	$string = is_string($string) ? $string : '';
101	$string = isset($string[0]) ? '~r2\|'.$string : '';
102
103	$key = self::key($key); // Get encryption key.
104	$key = substr($key, 0, @mcrypt_get_key_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_CBC));
105	$iv = c_ws_plugin__s2member_utils_strings::random_str_gen(@mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_CBC), false);
106
107	if (isset($string[0]) && is_string($e = @mcrypt_encrypt(MCRYPT_RIJNDAEL_256, $key, $string, MCRYPT_MODE_CBC, $iv)) && isset($e[0])) {
108	$e = '~r2:'.$iv.($w_md5_cs ? ':'.md5($e) : '').'\|'.$e;
109	}
110	return isset($e) && is_string($e) && isset($e[0])
111	? ($base64 = c_ws_plugin__s2member_utils_strings::base64_url_safe_encode($e))
112	: ''; // Default to empty string.
113	}
114	return self::xencrypt($string, $key, $w_md5_cs);
115	}
116
117	/**
118	* Decrypt w/ best possible technique.
119	*
120	* @since 3.5 Nearly the first release.
121	* @since 260810 Allows Defuse decryption on PHP 5.6+.
122	*
123	* @param string $base64 String to decrypt (base64).
124	* @param string $key Optional custom decryption key.
125	* @param bool\|null $allow_defuse Allow Defuse decryption as a better alternative?
126	*
127	* @return string Decrypted string, else empty string.
128	*/
129	public static function decrypt($base64 = '', $key = '', $allow_defuse = null)
130	{
131	if (!is_string($base64) \|\| !isset($base64[0])) {
132	return ''; // Not possible.
133	} // Fail when not a string or empty.
134
135	$allow_defuse = isset($allow_defuse) ? $allow_defuse
136	: apply_filters('c_ws_plugin__s2member_allow_defuse', true);
137
138	//260810 Allow PHP 5.6 to read Defuse ciphertext created on newer PHP versions; decryption was previously gated to PHP 7.0.4+.
139	// Defuse encryption remains gated separately so PHP 5.6 does not generate new Defuse ciphertext yet.
140	if ($allow_defuse && ($_d = c_ws_plugin__s2member_utils_defuse::decrypt($base64, $key))) {
141	return $string = $_d; // Defuse success.
142	}
143
144	if (function_exists('mcrypt_decrypt')
145	&& in_array('rijndael-256', @mcrypt_list_algorithms())
146	&& in_array('cbc', @mcrypt_list_modes())) {
147	//
148	$e = c_ws_plugin__s2member_utils_strings::base64_url_safe_decode($base64);
149
150	if (preg_match('/^~r2\:([a-zA-Z0-9]+)(?:\:([a-zA-Z0-9]+))?\\|(.*)$/s', $e, $iv_md5_e)) {
151	$key = self::key($key); // Get encryption key.
152	$key = substr($key, 0, @mcrypt_get_key_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_CBC));
153
154	if (isset($iv_md5_e[3][0]) && (empty($iv_md5_e[2]) \|\| $iv_md5_e[2] === md5($iv_md5_e[3]))) {
155	$d = @mcrypt_decrypt(MCRYPT_RIJNDAEL_256, $key, $iv_md5_e[3], MCRYPT_MODE_CBC, $iv_md5_e[1]);
156	}
157	if (!isset($d)) { // Failed above?
158	return ''; // Empty string on failure.
159	} elseif (!strlen($d = preg_replace('/^~r2\\|/', '', $d, 1, $r2)) \|\| !$r2) {
160	return ''; // Empty string on failure.
161	}
162	return $string = rtrim($d, "\0\4");
163	}
164	}
165	return self::xdecrypt($base64, $key);
166	}
167
168	/**
169	* XOR two-way encryption/decryption, with a base64 wrapper.
170	*
171	* @since 3.5 Nearly the first release.
172	*
173	* @param string $string A string of data to encrypt.
174	* @param string $key Optional. Key used for encryption. Defaults to the one configured for s2Member. Short of that, defaults to: ``wp_salt()``.
175	* @param bool $w_md5_cs Optional. Defaults to true. When true, an MD5 checksum is used in the encrypted string (recommended).
176	*
177	* @return string Encrypted string.
178	*/
179	public static function xencrypt($string = '', $key = '', $w_md5_cs = true)
180	{
181	$string = is_string($string) ? $string : '';
182	$string = isset($string[0]) ? '~xe\|'.$string : '';
183	$key = self::key($key); // Get encryption key.
184
185	for ($i = 1, $e = ''; $i <= strlen($string); ++$i) {
186	$char = substr($string, $i - 1, 1);
187	$keychar = substr($key, ($i % strlen($key)) - 1, 1);
188	//260830.2134 PHP 8.5 deprecates chr() values outside 0..255; mask explicitly to preserve chr()'s historical byte-wrap behavior.
189	$e .= chr((ord($char) + ord($keychar)) & 0xFF);
190	}
191	$e = isset($e[0]) ? '~xe'.($w_md5_cs ? ':'.md5($e) : '').'\|'.$e : '';
192	return $base64 = isset($e[0]) ? ($base64 = c_ws_plugin__s2member_utils_strings::base64_url_safe_encode($e)) : '';
193	}
194
195	/**
196	* XOR decryption.
197	*
198	* @since 3.5 Nearly the first release.
199	*
200	* @param string $base64 String to decrypt (base64).
201	* @param string $key Optional custom decryption key.
202	*
203	* @return string Decrypted string.
204	*/
205	public static function xdecrypt($base64 = '', $key = '')
206	{
207	if (!is_string($base64) \|\| !isset($base64[0])) {
208	return ''; // Not possible.
209	} // Fail when not a string or empty.
210
211	$e = c_ws_plugin__s2member_utils_strings::base64_url_safe_decode($base64);
212
213	if (preg_match('/^~xe(?:\:([a-zA-Z0-9]+))?\\|(.*)$/s', $e, $md5_e)) {
214	$key = self::key($key); // Get encryption key.
215
216	if (isset($md5_e[2][0]) && (empty($md5_e[1]) \|\| $md5_e[1] === md5($md5_e[2]))) {
217	for ($i = 1, $d = ''; $i <= strlen($md5_e[2]); ++$i) {
218	$char = substr($md5_e[2], $i - 1, 1);
219	$keychar = substr($key, ($i % strlen($key)) - 1, 1);
220	//260830.2134 PHP 8.5 deprecates chr() values outside 0..255; mask explicitly to preserve chr()'s historical byte-wrap behavior.
221	$d .= chr((ord($char) - ord($keychar)) & 0xFF);
222	} // Reverse XOR encryption.
223	} // Else the checksum was not a match.
224
225	if (!isset($d)) { // Failed above?
226	return ''; // Empty string on failure.
227	} elseif (!strlen($d = preg_replace('/^~xe\\|/', '', $d, 1, $xe)) \|\| !$xe) {
228	return ''; // Empty string on failure.
229	}
230	return $string = $d; // Decryption success.
231	}
232	return ''; // Empty string on failure.
233	}
234	}
235	}
236