In this thesis we follow two directions: Zero Knowledge Protocols and the Discrete Logarithm Problem. In each direction we present the necessary background and we give a new approach for some parts of the existing protocols., The new parts are…

We show that the long-standing assumption of "no-communication" between the provers of the two-prover model is not sufficiently precise to guarantee the security of a bit commitment scheme against malicious adversaries. Indeed, we show how a simple correlated random variable,…