2 namespace ParagonIE\ConstantTime;
5 * Copyright (c) 2016 Paragon Initiative Enterprises.
6 * Copyright (c) 2014 Steve "Sc00bz" Thomas (steve at tobtu dot com)
8 * Permission is hereby granted, free of charge, to any person obtaining a copy
9 * of this software and associated documentation files (the "Software"), to deal
10 * in the Software without restriction, including without limitation the rights
11 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
12 * copies of the Software, and to permit persons to whom the Software is
13 * furnished to do so, subject to the following conditions:
15 * The above copyright notice and this permission notice shall be included in all
16 * copies or substantial portions of the Software.
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
21 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
22 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
23 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
29 * @package ParagonIE\ConstantTime
31 abstract class Hex implements EncoderInterface
34 * Convert a binary string into a hexadecimal string without cache-timing
37 * @param string $bin_string (raw binary)
40 public static function encode($bin_string)
43 $len = Binary::safeStrlen($bin_string);
44 for ($i = 0; $i < $len; ++$i) {
45 $chunk = \unpack('C', Binary::safeSubstr($bin_string, $i, 2));
50 (87 + $b + ((($b - 10) >> 8) & ~38)),
51 (87 + $c + ((($c - 10) >> 8) & ~38))
58 * Convert a binary string into a hexadecimal string without cache-timing
59 * leaks, returning uppercase letters (as per RFC 4648)
61 * @param string $bin_string (raw binary)
64 public static function encodeUpper($bin_string)
67 $len = Binary::safeStrlen($bin_string);
68 for ($i = 0; $i < $len; ++$i) {
69 $chunk = \unpack('C', Binary::safeSubstr($bin_string, $i, 2));
74 (55 + $b + ((($b - 10) >> 8) & ~6)),
75 (55 + $c + ((($c - 10) >> 8) & ~6))
82 * Convert a hexadecimal string into a binary string without cache-timing
85 * @param string $hex_string
86 * @return string (raw binary)
87 * @throws \RangeException
89 public static function decode($hex_string)
94 $hex_len = Binary::safeStrlen($hex_string);
96 if (($hex_len & 1) !== 0) {
97 throw new \RangeException(
98 'Expected an even number of hexadecimal characters'
102 $chunk = \unpack('C*', $hex_string);
103 while ($hex_pos < $hex_len) {
105 $c = $chunk[$hex_pos];
107 $c_num0 = ($c_num - 10) >> 8;
108 $c_alpha = ($c & ~32) - 55;
109 $c_alpha0 = (($c_alpha - 10) ^ ($c_alpha - 16)) >> 8;
110 if (($c_num0 | $c_alpha0) === 0) {
111 throw new \RangeException(
112 'hexEncode() only expects hexadecimal characters'
115 $c_val = ($c_num0 & $c_num) | ($c_alpha & $c_alpha0);
117 $c_acc = $c_val * 16;
119 $bin .= \pack('C', $c_acc | $c_val);