On zero knowledge argument with PQT soundness

Abstract

Loosely speaking, an interactive argument is said to be zero knowledge if the view of every “efficient” verifier can be “efficiently” simulated. Recently, Pass relaxed the “efficient” adversaries and the simulator to be probabilistic quasi-polynomial time (PQT)) machines and proposed such a relaxed zero knowledge argument with computational soundness. In this paper, we present a relaxed zero knowledge protocol which achieves PQT soundness, instead of computational soundness. Also, it can be regarded as a stand-alone version of PMV scheme, with the difference that it is 5-round while PMV scheme is 6-round in the stand-alone setting. In addition, the simulation way determines that it is secure against PPT resettable-soundness attackers.