A novel approach to public-coin concurrent zero-knowledge and applications on resettable security

Canetti, Lin and Paneth in TCC 2013 showed a O(log;n) rounds public-coin concurrent zeroknowledge argument system（CZK） based on the existence of collision resistant hash functions, which is currently known as round optimal public-coin CZK from standard assumptions. In this paper, we further address this problem and present an alternative construction of public-coin CZK argument system with succinct slot. The key technique involves a new variant of Barak’s non-black-box simulate approach. In particular, the original protocol uses n commitments in each slot, while our construction uses one commitment in each slot. Through our simulation techniques, the simulator recovers any previous state needed for the probabilistically checkable proof（PCP） from the current committed state, which, in our view, may be of independent interest. Furthermore, the public-coin CZK argument system can be transformed into a resettable security protocol based on the one way functions assumption. Therefore, we present a new construction of the simultaneous resettable zero-knowledge argument system.