A note on efficient zero-knowledge proofs and arguments (Extended Abstract)
NEC Research Institute
Princeton, NJ 08540
In this note, we present new zero-knowledge interac-tive proofs and arguments for languages in NP. To show that z G L, with an error probability of at most 2-k, our zero-knowledge proof system requires O(lzlc’) + O(lg ” l~l)k ideal bit commitments, where c1 and cz depend only on L. This construction is the first in the ideal bit commitment model that achieves large values of k more efficiently than by running k independent iterations of the base interactive proof system. Under suitable complexity assumptions, we exhibit a zero-knowledge arguments that require O(lg ’ Izl)ki bits of communication, where c depends only on L, and 1 is the security parameter for the prover.l This is the first construction in which the total amount of communication can be less than that needed to transmit the NP witness. Our protocols are based on efficiently checkable proofs for NP .