Abstract : The communication scenario under consideration in this paper corresponds to a multiuser channel with side information and consists of a broadcast channel with two legitimate receivers and an eavesdropper. Mainly, the results obtained are as follows. First, an achievable rate region is provided for the (general) case of discrete-input discrete-output channels, generalizing existing results. Second, the obtained theorem is used to derive achievable transmission rates for two practical cases of Gaussian channels. It is shown that known perturbations can enlarge the rate region of broadcast wiretap channels with side information and having side information at the decoder as well can increase the secrecy rate of channels with side information. Third, we establish for the first time an explicit connection between multiuser channels and observation structures in dynamic games. In this respect, we show how to exploit the proved achievability theorem (discrete case) to derive a communication-compatible upper bound on the minmax level of a player.