Robust and secure identification

We determine the identification capacity of compound channels with and without wiretapper. It turned out, that the secure capacity formula fulfill a dichotomy theorem. It is positive if its secure capacity is positive and equals the transmission capacity of the channel. Otherwise the capacity is zero. We analyze the (dis-)continuity and (super-)additivity of the capacities, which we determined. Alon gave in [6] a conjecture about maximal violation for the additivity for capacity functions. We show that this maximal violation holds for the secure identification capacity. This is the first example of a capacity function, which has this behavior.