A Constant-Round Resettably-Sound Resettable Zero-Knowledge Argument in the BPK Model

In resetting attacks against a proof system, a prover or a verifier is reset and enforced to use the same random tape on various inputs as many times as an adversary may want. Recent deployment of cloud computing gives these attacks a new importance. This paper shows that argument systems for any NP language that are both resettably-sound and resettable zero-knowledge are possible by a constant-round protocol in the BPK model. For that sake, we define and construct a resettablyextractable conditional commitment scheme. keywords: resettable zero-knowledge, resettable soundness, conditional commitment, resettably extractable.