Interactive Locking, Zero-Knowledge PCPs, and Unconditional Cryptography

Motivated by the question of basing cryptographic protocols on stateless tamper-proof hardware tokens, we revisit the question of unconditional two-prover zero-knowledge proofs for NP. We show that such protocols exist in the interactive PCP model of Kalai and Raz (ICALP '08), where one of the provers is replaced by a PCP oracle. This strengthens the feasibility result of Ben-Or, Goldwasser, Kilian, and Wigderson (STOC '88) which requires two stateful provers. In contrast to previous zero-knowledge PCPs of Kilian, Petrank, and Tardos (STOC '97), in our protocol both the prover and the PCP oracle are efficient given an NP witness. Our main technical tool is a new primitive that we call interactive locking, an efficient realization of an unconditionally secure commitment scheme in the interactive PCP model. We implement interactive locking by adapting previous constructions of interactive hashing protocols to our setting, and also provide a direct construction which uses ...

• Type: Conference
• Year: 2010
• Where: CRYPTO
• Authors: Vipul Goyal, Yuval Ishai, Mohammad Mahmoody, Amit Sahai
• Keywords: CRYPTO 2010, Cryptology, Interactive Pcp Model, Stateless Tamper-proof Hardware, Tamper-proof Hardware Tokens