code: private function encrypt($plaintext) {
  		if (is_array($plaintext))
  			$ciphertext = json_encode($plaintext);
  		else
  			$ciphertext = $plaintext;
  
  		if ($this->status) {
  			$ciphertext = @mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $this->key, $ciphertext, MCRYPT_MODE_CBC, base64_decode($this->iv));
  		}
  
  		return base64_encode($ciphertext);
  	}
docs: encrypt
  ID: Enkripsi Session | EN: Session Encryption
  @param string $plaintext
  @return string