| Some results about the authentication codes are involved in the present paper. Firstly, we introduce some basic concepts. Secondly, one construction of Cartesian authentication code from norm form of one class of nilpotent matrices over finite field is presented and its size parameters are computed. Moreover, assume that the encoding rules are chosen according to a uniform probability distribution, the probabilities PI and PS, of a successful impersonation attack and of a successful substitution attack respectively, of these codes are also computed. |