Concurrent Zero Knowledge with Logarithmic Round-Complexity

We show that every language in NP has a (black-box) concurrent zero-knowledge proof system using ˜O(log n) rounds of interaction. The number of rounds in our protocol is optimal, in the sense that any language outside BPP requires at least ˜Ω(log n) rounds of interaction in order to be proved in black-box concurrent zero-knowledge. The zeroknowledge property of our main protocol is proved under the assumption that there exists a collection of claw-free functions. Assuming only the existence of one-way functions, we show the existence of ˜O(log n)-round concurrent zero-knowledge arguments for all languages in NP.

• Type: Conference
• Year: 2002
• Where: FOCS
• Authors: Manoj Prabhakaran, Alon Rosen, Amit Sahai
• Keywords: Black-box Concurrent Zero-knowledge, Concurrent Zero-knowledge, Concurrent Zero-knowledge Proof, FOCS 2002, Theoretical Computer Science