/**
  * Decrypt message
  *
  * @access public
  * @param string $encrypted 
  * @param integer $iterations
  * @return string
  */
 public function decrypt($encrypted, $iterations)
 {
     $key = $this->generateByIterations($this->keyseed, $iterations);
     $fernet = new Fernet($key);
     return $fernet->decode($encrypted);
 }