<?php /** * @package FrameworkOnFramework * @subpackage encrypt * @copyright Copyright (C) 2010-2016 Nicholas K. Dionysopoulos / Akeeba Ltd. All rights reserved. * @license GNU General Public License version 2 or later; see LICENSE.txt */ defined('FOF_INCLUDED') or die; /** * FOFEncryptBase32 * * @package FrameworkOnFramework * @since 1.0 */ class FOFEncryptBase32 { /** * CSRFC3548 * * The character set as defined by RFC3548 * @link http://www.ietf.org/rfc/rfc3548.txt */ const CSRFC3548 = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567'; /** * str2bin * * Converts any ascii string to a binary string * * @param string $str The string you want to convert * * @return string String of 0's and 1's */ private function str2bin($str) { $chrs = unpack('C*', $str); return vsprintf(str_repeat('%08b', count($chrs)), $chrs); } /** * bin2str * * Converts a binary string to an ascii string * * @param string $str The string of 0's and 1's you want to convert * * @return string The ascii output * * @throws Exception */ private function bin2str($str) { if (strlen($str) % 8 > 0) { throw new Exception('Length must be divisible by 8'); } if (!preg_match('/^[01]+$/', $str)) { throw new Exception('Only 0\'s and 1\'s are permitted'); } preg_match_all('/.{8}/', $str, $chrs); $chrs = array_map('bindec', $chrs[0]); // I'm just being slack here array_unshift($chrs, 'C*'); return call_user_func_array('pack', $chrs); } /** * fromBin * * Converts a correct binary string to base32 * * @param string $str The string of 0's and 1's you want to convert * * @return string String encoded as base32 * * @throws exception */ private function fromBin($str) { if (strlen($str) % 8 > 0) { throw new Exception('Length must be divisible by 8'); } if (!preg_match('/^[01]+$/', $str)) { throw new Exception('Only 0\'s and 1\'s are permitted'); } // Base32 works on the first 5 bits of a byte, so we insert blanks to pad it out $str = preg_replace('/(.{5})/', '000$1', $str); // We need a string divisible by 5 $length = strlen($str); $rbits = $length & 7; if ($rbits > 0) { // Excessive bits need to be padded $ebits = substr($str, $length - $rbits); $str = substr($str, 0, $length - $rbits); $str .= "000$ebits" . str_repeat('0', 5 - strlen($ebits)); } preg_match_all('/.{8}/', $str, $chrs); $chrs = array_map(array($this, '_mapcharset'), $chrs[0]); return join('', $chrs); } /** * toBin * * Accepts a base32 string and returns an ascii binary string * * @param string $str The base32 string to convert * * @return string Ascii binary string * * @throws Exception */ private function toBin($str) { if (!preg_match('/^[' . self::CSRFC3548 . ']+$/', $str)) { throw new Exception('Must match character set'); } // Convert the base32 string back to a binary string $str = join('', array_map(array($this, '_mapbin'), str_split($str))); // Remove the extra 0's we added $str = preg_replace('/000(.{5})/', '$1', $str); // Unpad if nessicary $length = strlen($str); $rbits = $length & 7; if ($rbits > 0) { $str = substr($str, 0, $length - $rbits); } return $str; } /** * fromString * * Convert any string to a base32 string * This should be binary safe... * * @param string $str The string to convert * * @return string The converted base32 string */ public function encode($str) { return $this->fromBin($this->str2bin($str)); } /** * toString * * Convert any base32 string to a normal sctring * This should be binary safe... * * @param string $str The base32 string to convert * * @return string The normal string */ public function decode($str) { $str = strtoupper($str); return $this->bin2str($this->tobin($str)); } /** * _mapcharset * * Used with array_map to map the bits from a binary string * directly into a base32 character set * * @param string $str The string of 0's and 1's you want to convert * * @return string Resulting base32 character * * @access private */ private function _mapcharset($str) { // Huh! $x = self::CSRFC3548; return $x[bindec($str)]; } /** * _mapbin * * Used with array_map to map the characters from a base32 * character set directly into a binary string * * @param string $chr The caracter to map * * @return string String of 0's and 1's * * @access private */ private function _mapbin($chr) { return sprintf('%08b', strpos(self::CSRFC3548, $chr)); } }