* @version 0.0.0
* @copyright Copyright (c) 2007, 2008 Roland Haeder, 2009 - 2011 Core Developer Team
* @license GNU GPL 3.0 or any newer version
* @link http://www.ship-simu.org
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see .
*/
class CryptoHelper extends BaseFrameworkSystem implements Cryptable {
// Exception constants
const EXCEPTION_ENCRYPT_MISSING = 0x1f0;
const EXCEPTION_ENCRYPT_INVALID = 0x1f1;
/**
* An instance of this own clas
*/
private static $selfInstance = null;
/**
* Instance of the crypto stream
*/
private $cryptoStreamInstance = null;
/**
* Salt for hashing operations
*/
private $salt = '';
/**
* Protected constructor
*
* @return void
*/
protected function __construct () {
// Call parent constructor
parent::__construct(__CLASS__);
}
/**
* Creates an instance of this class
*
* @return $cryptoInstance An instance of this crypto helper class
*/
public static final function createCryptoHelper () {
// Get a new instance
$cryptoInstance = new CryptoHelper();
// Initialize the hasher
$cryptoInstance->initHasher();
// Attach a crypto stream
$cryptoInstance->attachCryptoStream();
// Return the instance
return $cryptoInstance;
}
/**
* Get a singleton instance of this class
*
* @return $selfInstance An instance of this crypto helper class
*/
public static final function getInstance () {
// Is no instance there?
if (is_null(self::$selfInstance)) {
// Then get a new one
self::$selfInstance = self::createCryptoHelper();
} // END - if
// Return the instance
return self::$selfInstance;
}
/**
* Attaches a crypto stream to this crypto helper by detecting loaded
* modules.
*
* @return void
*/
protected function attachCryptoStream () {
// Do we have mcrypt loaded?
if ($this->isPhpExtensionLoaded('mcrypt')) {
// Then use it
$this->cryptoStreamInstance = ObjectFactory::createObjectByName('McryptStream', array($this->getRngInstance()));
} else {
// If nothing works ...
$this->cryptoStreamInstance = ObjectFactory::createObjectByName('NullCryptoStream');
}
}
/**
* Initializes the hasher for different purposes.
*
* @return void
*/
protected function initHasher () {
// Initialize the random number generator which is required by some crypto methods
$this->setRngInstance(ObjectFactory::createObjectByConfiguredName('rng_class'));
// Generate a salt for the hasher
$this->generateSalt();
}
/**
* Generates the salt based on configured length
*
* @return void
*/
private function generateSalt () {
// Get a random string from the RNG
$randomString = $this->getRngInstance()->randomString();
// Get config entry for salt length
$length = $this->getConfigInstance()->getConfigEntry('salt_length');
// Keep only defined number of characters
$this->salt = substr(sha1($randomString), -$length, $length);
}
/**
* Hashes a string with salt and returns the hash. If an old previous hash
* is supplied the method will use the first X chars of that hash for hashing
* the password. This is useful if you want to check if password is identical
* for authorization purposes.
*
* @param $str Unhashed string
* @param $oldHash A hash from previous hashed string
* @return $hashed The hashed and salted string
*/
public function hashString ($str, $oldHash = '') {
// Cast the string
$str = (string) $str;
// Default is the default salt ;-)
$salt = $this->salt;
// Is the old password set?
if (!empty($oldHash)) {
// Use the salt from hash, first get length
$length = $this->getConfigInstance()->getConfigEntry('salt_length');
// Then extract the X first characters from the hash as our salt
$salt = substr($oldHash, 0, $length);
} // END - if
// Hash the password with salt
//* DEBUG: */ echo "salt=".$salt."/plain=".$str."
\n";
$hashed = $salt . md5(sprintf($this->getConfigInstance()->getConfigEntry('hash_mask'),
$salt,
$this->getRngInstance()->getFixedSalt(),
$str
));
// And return it
return $hashed;
}
/**
* Encrypt the string with fixed salt
*
* @param $str The unencrypted string
* @param $key Optional key, if none provided, a random key will be generated
* @return $encrypted Encrypted string
*/
public function encryptString ($str, $key = null) {
// Encrypt the string through the stream
$encrypted = $this->cryptoStreamInstance->encryptStream($str, $key);
// Return the string
return $encrypted;
}
/**
* Decrypt the string with fixed salt
*
* @param $encrypted Encrypted string
* @return $str The unencrypted string
*/
public function decryptString ($encrypted) {
// Encrypt the string through the stream
$str = $this->cryptoStreamInstance->decryptStream($encrypted);
// Return the string
return $str;
}
}
// [EOF]
?>