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File: src/Base32.php

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File: src/Base32.php
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Content type: text/plain
Description: Class source
Class: PHP Constant Time String Encoding
Encode text without leaking context information
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Date: 5 years ago
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<?php declare(strict_types=1); namespace ParagonIE\ConstantTime; /** * Copyright (c) 2016 - 2018 Paragon Initiative Enterprises. * Copyright (c) 2014 Steve "Sc00bz" Thomas (steve at tobtu dot com) * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in all * copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE * SOFTWARE. */ /** * Class Base32 * [A-Z][2-7] * * @package ParagonIE\ConstantTime */ abstract class Base32 implements EncoderInterface { /** * Decode a Base32-encoded string into raw binary * * @param string $src * @return string * @throws \TypeError */ public static function decode(string $src, bool $strictPadding = false): string { return static::doDecode($src, false, $strictPadding); } /** * Decode an uppercase Base32-encoded string into raw binary * * @param string $src * @return string * @throws \TypeError */ public static function decodeUpper(string $src, bool $strictPadding = false): string { return static::doDecode($src, true, $strictPadding); } /** * Encode into Base32 (RFC 4648) * * @param string $src * @return string * @throws \TypeError */ public static function encode(string $src): string { return static::doEncode($src, false, true); } /** * Encode into Base32 (RFC 4648) * * @param string $src * @return string * @throws \TypeError */ public static function encodeUnpadded(string $src): string { return static::doEncode($src, false, false); } /** * Encode into uppercase Base32 (RFC 4648) * * @param string $src * @return string * @throws \TypeError */ public static function encodeUpper(string $src): string { return static::doEncode($src, true, true); } /** * Encode into uppercase Base32 (RFC 4648) * * @param string $src * @return string * @throws \TypeError */ public static function encodeUpperUnpadded(string $src): string { return static::doEncode($src, true, false); } /** * Uses bitwise operators instead of table-lookups to turn 5-bit integers * into 8-bit integers. * * @param int $src * @return int */ protected static function decode5Bits(int $src): int { $ret = -1; // if ($src > 96 && $src < 123) $ret += $src - 97 + 1; // -64 $ret += (((0x60 - $src) & ($src - 0x7b)) >> 8) & ($src - 96); // if ($src > 0x31 && $src < 0x38) $ret += $src - 24 + 1; // -23 $ret += (((0x31 - $src) & ($src - 0x38)) >> 8) & ($src - 23); return $ret; } /** * Uses bitwise operators instead of table-lookups to turn 5-bit integers * into 8-bit integers. * * Uppercase variant. * * @param int $src * @return int */ protected static function decode5BitsUpper(int $src): int { $ret = -1; // if ($src > 64 && $src < 91) $ret += $src - 65 + 1; // -64 $ret += (((0x40 - $src) & ($src - 0x5b)) >> 8) & ($src - 64); // if ($src > 0x31 && $src < 0x38) $ret += $src - 24 + 1; // -23 $ret += (((0x31 - $src) & ($src - 0x38)) >> 8) & ($src - 23); return $ret; } /** * Uses bitwise operators instead of table-lookups to turn 8-bit integers * into 5-bit integers. * * @param int $src * @return string */ protected static function encode5Bits(int $src): string { $diff = 0x61; // if ($src > 25) $ret -= 72; $diff -= ((25 - $src) >> 8) & 73; return \pack('C', $src + $diff); } /** * Uses bitwise operators instead of table-lookups to turn 8-bit integers * into 5-bit integers. * * Uppercase variant. * * @param int $src * @return string */ protected static function encode5BitsUpper(int $src): string { $diff = 0x41; // if ($src > 25) $ret -= 40; $diff -= ((25 - $src) >> 8) & 41; return \pack('C', $src + $diff); } /** * Base32 decoding * * @param string $src * @param bool $upper * @param bool $strictPadding * @return string * @throws \TypeError * @psalm-suppress RedundantCondition */ protected static function doDecode(string $src, bool $upper = false, bool $strictPadding = false): string { // We do this to reduce code duplication: $method = $upper ? 'decode5BitsUpper' : 'decode5Bits'; // Remove padding $srcLen = Binary::safeStrlen($src); if ($srcLen === 0) { return ''; } if ($strictPadding) { if (($srcLen & 7) === 0) { for ($j = 0; $j < 7; ++$j) { if ($src[$srcLen - 1] === '=') { $srcLen--; } else { break; } } } if (($srcLen & 7) === 1) { throw new \RangeException( 'Incorrect padding' ); } } else { $src = \rtrim($src, '='); $srcLen = Binary::safeStrlen($src); } $err = 0; $dest = ''; // Main loop (no padding): for ($i = 0; $i + 8 <= $srcLen; $i += 8) { /** @var array<int, int> $chunk */ $chunk = \unpack('C*', Binary::safeSubstr($src, $i, 8)); /** @var int $c0 */ $c0 = static::$method($chunk[1]); /** @var int $c1 */ $c1 = static::$method($chunk[2]); /** @var int $c2 */ $c2 = static::$method($chunk[3]); /** @var int $c3 */ $c3 = static::$method($chunk[4]); /** @var int $c4 */ $c4 = static::$method($chunk[5]); /** @var int $c5 */ $c5 = static::$method($chunk[6]); /** @var int $c6 */ $c6 = static::$method($chunk[7]); /** @var int $c7 */ $c7 = static::$method($chunk[8]); $dest .= \pack( 'CCCCC', (($c0 << 3) | ($c1 >> 2) ) & 0xff, (($c1 << 6) | ($c2 << 1) | ($c3 >> 4)) & 0xff, (($c3 << 4) | ($c4 >> 1) ) & 0xff, (($c4 << 7) | ($c5 << 2) | ($c6 >> 3)) & 0xff, (($c6 << 5) | ($c7 ) ) & 0xff ); $err |= ($c0 | $c1 | $c2 | $c3 | $c4 | $c5 | $c6 | $c7) >> 8; } // The last chunk, which may have padding: if ($i < $srcLen) { /** @var array<int, int> $chunk */ $chunk = \unpack('C*', Binary::safeSubstr($src, $i, $srcLen - $i)); /** @var int $c0 */ $c0 = static::$method($chunk[1]); if ($i + 6 < $srcLen) { /** @var int $c1 */ $c1 = static::$method($chunk[2]); /** @var int $c2 */ $c2 = static::$method($chunk[3]); /** @var int $c3 */ $c3 = static::$method($chunk[4]); /** @var int $c4 */ $c4 = static::$method($chunk[5]); /** @var int $c5 */ $c5 = static::$method($chunk[6]); /** @var int $c6 */ $c6 = static::$method($chunk[7]); $dest .= \pack( 'CCCC', (($c0 << 3) | ($c1 >> 2) ) & 0xff, (($c1 << 6) | ($c2 << 1) | ($c3 >> 4)) & 0xff, (($c3 << 4) | ($c4 >> 1) ) & 0xff, (($c4 << 7) | ($c5 << 2) | ($c6 >> 3)) & 0xff ); $err |= ($c0 | $c1 | $c2 | $c3 | $c4 | $c5 | $c6) >> 8; } elseif ($i + 5 < $srcLen) { /** @var int $c1 */ $c1 = static::$method($chunk[2]); /** @var int $c2 */ $c2 = static::$method($chunk[3]); /** @var int $c3 */ $c3 = static::$method($chunk[4]); /** @var int $c4 */ $c4 = static::$method($chunk[5]); /** @var int $c5 */ $c5 = static::$method($chunk[6]); $dest .= \pack( 'CCCC', (($c0 << 3) | ($c1 >> 2) ) & 0xff, (($c1 << 6) | ($c2 << 1) | ($c3 >> 4)) & 0xff, (($c3 << 4) | ($c4 >> 1) ) & 0xff, (($c4 << 7) | ($c5 << 2) ) & 0xff ); $err |= ($c0 | $c1 | $c2 | $c3 | $c4 | $c5) >> 8; } elseif ($i + 4 < $srcLen) { /** @var int $c1 */ $c1 = static::$method($chunk[2]); /** @var int $c2 */ $c2 = static::$method($chunk[3]); /** @var int $c3 */ $c3 = static::$method($chunk[4]); /** @var int $c4 */ $c4 = static::$method($chunk[5]); $dest .= \pack( 'CCC', (($c0 << 3) | ($c1 >> 2) ) & 0xff, (($c1 << 6) | ($c2 << 1) | ($c3 >> 4)) & 0xff, (($c3 << 4) | ($c4 >> 1) ) & 0xff ); $err |= ($c0 | $c1 | $c2 | $c3 | $c4) >> 8; } elseif ($i + 3 < $srcLen) { /** @var int $c1 */ $c1 = static::$method($chunk[2]); /** @var int $c2 */ $c2 = static::$method($chunk[3]); /** @var int $c3 */ $c3 = static::$method($chunk[4]); $dest .= \pack( 'CC', (($c0 << 3) | ($c1 >> 2) ) & 0xff, (($c1 << 6) | ($c2 << 1) | ($c3 >> 4)) & 0xff ); $err |= ($c0 | $c1 | $c2 | $c3) >> 8; } elseif ($i + 2 < $srcLen) { /** @var int $c1 */ $c1 = static::$method($chunk[2]); /** @var int $c2 */ $c2 = static::$method($chunk[3]); $dest .= \pack( 'CC', (($c0 << 3) | ($c1 >> 2) ) & 0xff, (($c1 << 6) | ($c2 << 1) ) & 0xff ); $err |= ($c0 | $c1 | $c2) >> 8; } elseif ($i + 1 < $srcLen) { /** @var int $c1 */ $c1 = static::$method($chunk[2]); $dest .= \pack( 'C', (($c0 << 3) | ($c1 >> 2) ) & 0xff ); $err |= ($c0 | $c1) >> 8; } else { $dest .= \pack( 'C', (($c0 << 3) ) & 0xff ); $err |= ($c0) >> 8; } } /** @var bool $check */ $check = ($err === 0); if (!$check) { throw new \RangeException( 'Base32::doDecode() only expects characters in the correct base32 alphabet' ); } return $dest; } /** * Base32 Encoding * * @param string $src * @param bool $upper * @param bool $pad * @return string * @throws \TypeError */ protected static function doEncode(string $src, bool $upper = false, $pad = true): string { // We do this to reduce code duplication: $method = $upper ? 'encode5BitsUpper' : 'encode5Bits'; $dest = ''; $srcLen = Binary::safeStrlen($src); // Main loop (no padding): for ($i = 0; $i + 5 <= $srcLen; $i += 5) { /** @var array<int, int> $chunk */ $chunk = \unpack('C*', Binary::safeSubstr($src, $i, 5)); $b0 = $chunk[1]; $b1 = $chunk[2]; $b2 = $chunk[3]; $b3 = $chunk[4]; $b4 = $chunk[5]; $dest .= static::$method( ($b0 >> 3) & 31) . static::$method((($b0 << 2) | ($b1 >> 6)) & 31) . static::$method((($b1 >> 1) ) & 31) . static::$method((($b1 << 4) | ($b2 >> 4)) & 31) . static::$method((($b2 << 1) | ($b3 >> 7)) & 31) . static::$method((($b3 >> 2) ) & 31) . static::$method((($b3 << 3) | ($b4 >> 5)) & 31) . static::$method( $b4 & 31); } // The last chunk, which may have padding: if ($i < $srcLen) { /** @var array<int, int> $chunk */ $chunk = \unpack('C*', Binary::safeSubstr($src, $i, $srcLen - $i)); $b0 = $chunk[1]; if ($i + 3 < $srcLen) { $b1 = $chunk[2]; $b2 = $chunk[3]; $b3 = $chunk[4]; $dest .= static::$method( ($b0 >> 3) & 31) . static::$method((($b0 << 2) | ($b1 >> 6)) & 31) . static::$method((($b1 >> 1) ) & 31) . static::$method((($b1 << 4) | ($b2 >> 4)) & 31) . static::$method((($b2 << 1) | ($b3 >> 7)) & 31) . static::$method((($b3 >> 2) ) & 31) . static::$method((($b3 << 3) ) & 31); if ($pad) { $dest .= '='; } } elseif ($i + 2 < $srcLen) { $b1 = $chunk[2]; $b2 = $chunk[3]; $dest .= static::$method( ($b0 >> 3) & 31) . static::$method((($b0 << 2) | ($b1 >> 6)) & 31) . static::$method((($b1 >> 1) ) & 31) . static::$method((($b1 << 4) | ($b2 >> 4)) & 31) . static::$method((($b2 << 1) ) & 31); if ($pad) { $dest .= '==='; } } elseif ($i + 1 < $srcLen) { $b1 = $chunk[2]; $dest .= static::$method( ($b0 >> 3) & 31) . static::$method((($b0 << 2) | ($b1 >> 6)) & 31) . static::$method((($b1 >> 1) ) & 31) . static::$method((($b1 << 4) ) & 31); if ($pad) { $dest .= '===='; } } else { $dest .= static::$method( ($b0 >> 3) & 31) . static::$method( ($b0 << 2) & 31); if ($pad) { $dest .= '======'; } } } return $dest; } }