Multiple Access Wiretap channels with strong secrecy

The problem of secure communication over Multiple-Access Wiretap channel (MAC-WTC) under strong secrecy criterion is investigated. A new technique based on channel output statistics approximation is developed for establishing the strong security over multi-user channels. In particular, this technique shows that how simple wiretap coding results in secure communication under strong secrecy criterion instead of weak secrecy criterion. As a side result of the paper, two results on the output statistics of MAC are provided. Such results can be used to approximate the mutual information between input and output of MAC with respect to a given codebook of arbitrary rate.