Key Distribution Protocols Based on Noisy Channels in Presence of an Active Adversary: Conventional and New Versions With Parameter Optimization

In this paper, we consider the information-theoretic secure key distribution problem over noisy wiretap channels with public discussion and in the presence of an active adversary. There are several well-known versions of the protocols proposed by Maurer and Wolf to solve this problem. We describe several new versions of the key distribution protocols for the same channel model allowing to increase the key rate given a fixed key security and under an optimization of the protocol parameters. Both asymptotic and nonasymptotic cases are presented. It is shown that in some cases the nonasymptotic key rate is not so far from the asymptotic one whenever the lengths of the transmitted strings are of the order of thousands of bits.