two-factor-authentication / Base32 / Base32.php

Base32.php in Two Factor Authentication 1.2.6, at Base32/Base32.php

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1	<?php
2	//namespace Base32;
3
4	/**
5	* Base32 encoder and decoder
6	*
7	* Last update: 2012-06-20
8	*
9	* RFC 4648 compliant
10	* @link http://www.ietf.org/rfc/rfc4648.txt
11	*
12	* Some groundwork based on this class
13	* https://github.com/NTICompass/PHP-Base32
14	*
15	* @author Christian Riesen <chris.riesen@gmail.com>
16	* @link http://christianriesen.com
17	* @license MIT License see LICENSE file
18	*/
19	class Base32
20	{
21	/**
22	* Table for encoding base32
23	*
24	* @var array
25	*/
26	private static $encode = array(
27	0 => 'A',
28	1 => 'B',
29	2 => 'C',
30	3 => 'D',
31	4 => 'E',
32	5 => 'F',
33	6 => 'G',
34	7 => 'H',
35	8 => 'I',
36	9 => 'J',
37	10 => 'K',
38	11 => 'L',
39	12 => 'M',
40	13 => 'N',
41	14 => 'O',
42	15 => 'P',
43	16 => 'Q',
44	17 => 'R',
45	18 => 'S',
46	19 => 'T',
47	20 => 'U',
48	21 => 'V',
49	22 => 'W',
50	23 => 'X',
51	24 => 'Y',
52	25 => 'Z',
53	26 => 2,
54	27 => 3,
55	28 => 4,
56	29 => 5,
57	30 => 6,
58	31 => 7,
59	32 => '=',
60	);
61
62	/**
63	* Table for decoding base32
64	*
65	* @var array
66	*/
67	private static $decode = array(
68	'A' => 0,
69	'B' => 1,
70	'C' => 2,
71	'D' => 3,
72	'E' => 4,
73	'F' => 5,
74	'G' => 6,
75	'H' => 7,
76	'I' => 8,
77	'J' => 9,
78	'K' => 10,
79	'L' => 11,
80	'M' => 12,
81	'N' => 13,
82	'O' => 14,
83	'P' => 15,
84	'Q' => 16,
85	'R' => 17,
86	'S' => 18,
87	'T' => 19,
88	'U' => 20,
89	'V' => 21,
90	'W' => 22,
91	'X' => 23,
92	'Y' => 24,
93	'Z' => 25,
94	2 => 26,
95	3 => 27,
96	4 => 28,
97	5 => 29,
98	6 => 30,
99	7 => 31,
100	'=' => 32,
101	);
102
103	/**
104	* Creates an array from a binary string into a given chunk size
105	*
106	* @param string $binaryString String to chunk
107	* @param integer $bits Number of bits per chunk
108	* @return array
109	*/
110	private static function chunk($binaryString, $bits)
111	{
112	$binaryString = chunk_split($binaryString, $bits, ' ');
113
114	if (substr($binaryString, (strlen($binaryString)) - 1) == ' ') {
115	$binaryString = substr($binaryString, 0, strlen($binaryString)-1);
116	}
117
118	return explode(' ', $binaryString);
119	}
120
121	/**
122	* Encodes into base32
123	*
124	* @param string $string Clear text string
125	* @return string Base32 encoded string
126	*/
127	public static function encode($string)
128	{
129	if (strlen($string) == 0) {
130	// Gives an empty string
131	return '';
132	}
133
134	// Convert string to binary
135	$binaryString = '';
136
137	foreach (str_split($string) as $s) {
138	// Return each character as an 8-bit binary string
139	$s = decbin(ord($s));
140	$binaryString .= str_pad($s, 8, 0, STR_PAD_LEFT);
141	}
142
143	// Break into 5-bit chunks, then break that into an array
144	$binaryArray = self::chunk($binaryString, 5);
145
146	// Pad array to be divisible by 8
147	while (count($binaryArray) % 8 !== 0) {
148	$binaryArray[] = null;
149	}
150
151	$base32String = '';
152
153	// Encode in base32
154	foreach ($binaryArray as $bin) {
155	$char = 32;
156
157	if (!is_null($bin)) {
158	// Pad the binary strings
159	$bin = str_pad($bin, 5, 0, STR_PAD_RIGHT);
160	$char = bindec($bin);
161	}
162
163	// Base32 character
164	$base32String .= self::$encode[$char];
165	}
166
167	return $base32String;
168	}
169
170	/**
171	* Decodes base32
172	*
173	* @param string $base32String Base32 encoded string
174	* @return string Clear text string
175	*/
176	public static function decode($base32String)
177	{
178	if (strlen($base32String) == 0) {
179	// Gives an empty string
180	return '';
181	}
182
183	// Only work in upper cases
184	$base32String = strtoupper($base32String);
185
186	// Remove anything that is not base32 alphabet
187	$pattern = '/[^A-Z2-7]/';
188	$replacement = '';
189
190	$base32String = preg_replace($pattern, '', $base32String);
191
192	$base32Array = str_split($base32String);
193
194	$binaryArray = array();
195	$string = '';
196
197	foreach ($base32Array as $str) {
198	$char = self::$decode[$str];
199
200	// Ignore the padding character
201	if ($char !== 32) {
202	$char = decbin($char);
203	$string .= str_pad($char, 5, 0, STR_PAD_LEFT);
204	}
205	}
206
207	while (strlen($string) %8 !== 0) {
208	$string = substr($string, 0, strlen($string)-1);
209	}
210
211	$binaryArray = self::chunk($string, 8);
212
213	$realString = '';
214
215	foreach ($binaryArray as $bin) {
216	// Pad each value to 8 bits
217	$bin = str_pad($bin, 8, 0, STR_PAD_RIGHT);
218	// Convert binary strings to ascii
219	$realString .= chr(bindec($bin));
220	}
221
222	return $realString;
223	}
224	}
225
226