primo commit

libraries/fof30/Encrypt/Base32.php

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+<?php
+/**
+ * @package   FOF
+ * @copyright Copyright (c)2010-2021 Nicholas K. Dionysopoulos / Akeeba Ltd
+ * @license   GNU General Public License version 2, or later
+ */
+
+namespace FOF30\Encrypt;
+
+defined('_JEXEC') || die;
+
+use InvalidArgumentException;
+
+/**
+ * Base32 encoding class, used by the TOTP
+ */
+class Base32
+{
+	/**
+	 * CSRFC3548
+	 *
+	 * The character set as defined by RFC3548
+	 * @link http://www.ietf.org/rfc/rfc3548.txt
+	 */
+	public const CSRFC3548 = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567';
+
+	/**
+	 * 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));
+	}
+
+	/**
+	 * 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));
+	}
+
+	/**
+	 * 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);
+	}
+
+	/**
+	 * Converts a binary string to an ascii string
+	 *
+	 * @param   string  $str  The string of 0's and 1's you want to convert
+	 *
+	 * @return  string  The ascii output
+	 *
+	 * @throws  InvalidArgumentException
+	 */
+	private function bin2str($str)
+	{
+		if (strlen($str) % 8 > 0)
+		{
+			throw new InvalidArgumentException('Length must be divisible by 8');
+		}
+
+		if (!preg_match('/^[01]+$/', $str))
+		{
+			throw new InvalidArgumentException('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);
+	}
+
+	/**
+	 * Converts a correct binary string to base32
+	 *
+	 * @param   string  $str  The string of 0's and 1's you want to convert
+	 *
+	 * @return  string  String encoded as base32
+	 *
+	 * @throws  InvalidArgumentException
+	 */
+	private function fromBin($str)
+	{
+		if (strlen($str) % 8 > 0)
+		{
+			throw new InvalidArgumentException('Length must be divisible by 8');
+		}
+
+		if (!preg_match('/^[01]+$/', $str))
+		{
+			throw new InvalidArgumentException('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);
+		$chrs = array_map([$this, 'mapCharset'], $chrs[0]);
+
+		return implode('', $chrs);
+	}
+
+	/**
+	 * Accepts a base32 string and returns an ascii binary string
+	 *
+	 * @param   string  $str  The base32 string to convert
+	 *
+	 * @return  string  Ascii binary string
+	 *
+	 * @throws  InvalidArgumentException
+	 */
+	private function toBin($str)
+	{
+		if (!preg_match('/^[' . self::CSRFC3548 . ']+$/', $str))
+		{
+			throw new InvalidArgumentException('Base64 string must match character set');
+		}
+
+		// Convert the base32 string back to a binary string
+		$str = implode('', array_map([$this, 'mapBin'], str_split($str)));
+
+		// Remove the extra 0's we added
+		$str = preg_replace('/000(.{5})/', '$1', $str);
+
+		// Remove padding if necessary
+		$length = strlen($str);
+		$rbits  = $length & 7;
+
+		if ($rbits > 0)
+		{
+			$str = substr($str, 0, $length - $rbits);
+		}
+
+		return $str;
+	}
+
+	/**
+	 * 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)];
+	}
+
+	/**
+	 * Used with array_map to map the characters from a base32
+	 * character set directly into a binary string
+	 *
+	 * @param   string  $chr  The character to map
+	 *
+	 * @return  string  String of 0's and 1's
+	 *
+	 * @access private
+	 */
+	private function mapBin($chr)
+	{
+		return sprintf('%08b', strpos(self::CSRFC3548, $chr));
+	}
+
+}