Which Languages Have 4-Round Zero-Knowledge Proofs?

We show that if a language L has a 4-round, black-box, computational zero-knowledge proof system with negligible soundness error, then ¯L ∈ MA. Assuming the polynomial hierarchy does not collapse, this means in particular that NP-complete languages do not have 4-round zero-knowledge proofs (at least with respect to black-box simulation).

• Type: Journal
• Year: 2007
• Where: ECCC
• Authors: Jonathan Katz
• Keywords: 4-round Zero-knowledge Proofs, Black-box, ECCC 2007, Negligible Soundness Error