Abstract: A security system encrypts the password on an operator interface terminal without storing the password and sends the encrypted password to a programmable logic controller, where the password is again encrypted. The multiple-encrypted password is stored on the programmable logic controller. Even if an unauthorized individual were able to see the multiple-encrypted password, it would be difficult for the unauthorized individual to deduce the original password from the multiple-encrypted password. Accesses and changes of parameters are tracked and reportable.