Impossibility and Feasibility Results for Zero Knowledge with Public Keys

In this paper, we continue the study the round complexity of black-box zero knowledge in the bare public-key (BPK, for short) model previously started by Micali and Reyzin in [11]. Specifically we show the impossibility of 3-round concurrent (and thus resettable) black-box zeroknowledge argument systems with sequential soundness for non-trivial languages. In light of the previous state-of-the-art, our result completes the analysis of the round complexity of black-box zero knowledge in the BPK model with respect to the notions of soundness and black-box zero knowledge. Further we give sufficient conditions for the existence of a 3-round resettable zero-knowledge proof (in contrast to argument) system with concurrent soundness for NP in the upperbounded public-key model introduced in [14].

• Type: Conference
• Year: 2005
• Where: CRYPTO
• Authors: Joël Alwen, Giuseppe Persiano, Ivan Visconti
• Keywords: Black-box Zero Knowledge, Black-box Zeroknowledge Argument, CRYPTO 2005, Knowledge In