On the Composition of Public-Coin Zero-Knowledge Protocols

Abstract. We show that only languages in BPP have public-coin, blackbox zero-knowledge protocols that are secure under an unbounded (polynomial) number of parallel repetitions. This result holds both in the plain model (without any set-up) and in the Bare Public-Key Model (where the prover and the verifier have registered public keys). We complement this result by showing the existence of a public-coin black-box zero-knowledge proof that remains secure under any a-priori bounded number of concurrent executions.

• Type: Conference
• Year: 2009
• Where: CRYPTO
• Authors: Rafael Pass, Wei-Lung Dustin Tseng, Douglas Wikström
• Keywords: Bare Public-Key Model, Black-box Zero-knowledge Proof, Blackbox Zero-knowledge Protocols, CRYPTO 2009, Cryptology