<?php
/**
* @package Joomla.Platform
* @subpackage Crypt
*
* @copyright Copyright (C) 2005 - 2014 Open Source Matters, Inc. All rights reserved.
* @license GNU General Public License version 2 or later; see LICENSE
*/
defined('JPATH_PLATFORM') or die;
/**
* JCrypt cipher for Simple encryption, decryption and key generation.
*
* @package Joomla.Platform
* @subpackage Crypt
* @since 12.1
*/
class JCryptCipherSimple implements JCryptCipher
{
/**
* Method to decrypt a data string.
*
* @param string $data The encrypted string to decrypt.
* @param JCryptKey $key The key[/pair] object to use for decryption.
*
* @return string The decrypted data string.
*
* @since 12.1
* @throws InvalidArgumentException
*/
public function decrypt($data, JCryptKey $key)
{
// Validate key.
if ($key->type != 'simple')
{
throw new InvalidArgumentException('Invalid key of type: ' . $key->type . '. Expected simple.');
}
// Initialise variables.
$decrypted = '';
$tmp = $key->public;
// Convert the HEX input into an array of integers and get the number of characters.
$chars = $this->_hexToIntArray($data);
$charCount = count($chars);
// Repeat the key as many times as necessary to ensure that the key is at least as long as the input.
for ($i = 0; $i < $charCount; $i = strlen($tmp))
{
$tmp = $tmp . $tmp;
}
// Get the XOR values between the ASCII values of the input and key characters for all input offsets.
for ($i = 0; $i < $charCount; $i++)
{
$decrypted .= chr($chars[$i] ^ ord($tmp[$i]));
}
return $decrypted;
}
/**
* Method to encrypt a data string.
*
* @param string $data The data string to encrypt.
* @param JCryptKey $key The key[/pair] object to use for encryption.
*
* @return string The encrypted data string.
*
* @since 12.1
* @throws InvalidArgumentException
*/
public function encrypt($data, JCryptKey $key)
{
// Validate key.
if ($key->type != 'simple')
{
throw new InvalidArgumentException('Invalid key of type: ' . $key->type . '. Expected simple.');
}
// Initialise variables.
$encrypted = '';
$tmp = $key->private;
// Split up the input into a character array and get the number of characters.
$chars = preg_split('//', $data, -1, PREG_SPLIT_NO_EMPTY);
$charCount = count($chars);
// Repeat the key as many times as necessary to ensure that the key is at least as long as the input.
for ($i = 0; $i < $charCount; $i = strlen($tmp))
{
$tmp = $tmp . $tmp;
}
// Get the XOR values between the ASCII values of the input and key characters for all input offsets.
for ($i = 0; $i < $charCount; $i++)
{
$encrypted .= $this->_intToHex(ord($tmp[$i]) ^ ord($chars[$i]));
}
return $encrypted;
}
/**
* Method to generate a new encryption key[/pair] object.
*
* @param array $options Key generation options.
*
* @return JCryptKey
*
* @since 12.1
*/
public function generateKey(array $options = array())
{
// Create the new encryption key[/pair] object.
$key = new JCryptKey('simple');
// Just a random key of a given length.
$key->private = $this->_getRandomKey();
$key->public = $key->private;
return $key;
}
/**
* Method to generate a random key of a given length.
*
* @param integer $length The length of the key to generate.
*
* @return string
*
* @since 12.1
*/
private function _getRandomKey($length = 256)
{
// Initialise variables.
$key = '';
$salt = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
$saltLength = strlen($salt);
// Build the random key.
for ($i = 0; $i < $length; $i++)
{
$key .= $salt[mt_rand(0, $saltLength - 1)];
}
return $key;
}
/**
* Convert hex to an integer
*
* @param string $s The hex string to convert.
* @param integer $i The offset?
*
* @return integer
*
* @since 11.1
*/
private function _hexToInt($s, $i)
{
// Initialise variables.
$j = (int) $i * 2;
$k = 0;
$s1 = (string) $s;
// Get the character at position $j.
$c = substr($s1, $j, 1);
// Get the character at position $j + 1.
$c1 = substr($s1, $j + 1, 1);
switch ($c)
{
case 'A':
$k += 160;
break;
case 'B':
$k += 176;
break;
case 'C':
$k += 192;
break;
case 'D':
$k += 208;
break;
case 'E':
$k += 224;
break;
case 'F':
$k += 240;
break;
case ' ':
$k += 0;
break;
default:
(int) $k = $k + (16 * (int) $c);
break;
}
switch ($c1)
{
case 'A':
$k += 10;
break;
case 'B':
$k += 11;
break;
case 'C':
$k += 12;
break;
case 'D':
$k += 13;
break;
case 'E':
$k += 14;
break;
case 'F':
$k += 15;
break;
case ' ':
$k += 0;
break;
default:
$k += (int) $c1;
break;
}
return $k;
}
/**
* Convert hex to an array of integers
*
* @param string $hex The hex string to convert to an integer array.
*
* @return array An array of integers.
*
* @since 11.1
*/
private function _hexToIntArray($hex)
{
// Initialise variables.
$array = array();
$j = (int) strlen($hex) / 2;
for ($i = 0; $i < $j; $i++)
{
$array[$i] = (int) $this->_hexToInt($hex, $i);
}
return $array;
}
/**
* Convert an integer to a hexadecimal string.
*
* @param integer $i An integer value to convert to a hex string.
*
* @return string
*
* @since 11.1
*/
private function _intToHex($i)
{
// Sanitize the input.
$i = (int) $i;
// Get the first character of the hexadecimal string if there is one.
$j = (int) ($i / 16);
if ($j === 0)
{
$s = ' ';
}
else
{
$s = strtoupper(dechex($j));
}
// Get the second character of the hexadecimal string.
$k = $i - $j * 16;
$s = $s . strtoupper(dechex($k));
return $s;
}
}
