4-Round Resettably-Sound Zero Knowledge.

While 4-round constructions of zero-knowledge arguments are known based on the existence of one-way functions, constuctions of resettably-sound zero-knowledge arguments require either stronger assumptions (the existence of a fully-homomorphic encryption scheme), or more communication rounds. We close this gap by demonstrating a 4round resettably-sound zero-knowledge argument for NP based on the existence of one-way functions.