private static function decryptRSA($string)
 {
     $errorSettings = error_reporting(0);
     $pemString = file_get_contents('key.pem');
     $keyPair = Crypt_RSA_KeyPair::fromPEMString($pemString);
     $math_obj =& Crypt_RSA_MathLoader::loadWrapper('default');
     $rsa = new Crypt_RSA(array('dec_key' => $keyPair->getPrivateKey()));
     $cleartext = $rsa->decryptBinary($math_obj->int2bin($string));
     error_reporting($errorSettings);
     return $cleartext;
 }