Unconditionally Secure NIZK in the Fine-Grained Setting

Non-interactive zero-knowledge (NIZK) proof systems are often constructed based on cryptographic assumptions. In this paper, we propose the first unconditionally secure NIZK system in the AC(0)-finegrained setting. More precisely, our NIZK system has perfect soundness for all adversaries and unconditional zero-knowledge for AC(0) adversaries, namely, an AC(0) adversary can only break the zero-knowledge property with negligible probability unconditionally. At the core of our construction is an OR-proof system for satisfiability of 1 out of polynomial many statements.