  Adding input and output noises for increasing model identification error of
finite impulse response (FIR) systems is considered. This is motivated by the
desire to protect the model of the system as a trade secret by rendering model
identification techniques ineffective. Optimal filters for constructing
additive noises that maximizes the identification error subject to maintaining
the closed-loop performance degradation below a limit are constructed.
Furthermore, differential privacy is used for designing output noises that
preserve the privacy of the model.
