Compactly Hiding Linear Spans - Tightly Secure Constant-Size Simulation-Sound QA-NIZK Proofs and Applications

Quasi-adaptive non-interactive zero-knowledge (QA-NIZK) proofs is a recent paradigm, suggested by Jutla and Roy (Asiacrypt ’13), which is motivated by the Groth-Sahai seminal techniques for efficient non-interactive zero-knowledge (NIZK) proofs. In this paradigm, the common reference string may depend on specific language parameters, a fact that allows much shorter proofs in important cases. It even makes certain standard model applications competitive with the Fiat-Shamir heuristic in the Random Oracle idealization. Such QA-NIZK proofs were recently optimized to constant size by Jutla and Roy (Crypto ’14) and Libert et al. (Eurocrypt ’14) for the important case of proving that a vector of group elements belongs to a linear subspace. While the QA-NIZK arguments of Libert et al. provide unbounded simulationsoundness and constant proof length, their simulation-soundness is only loosely related to the underlying assumption (with a gap proportional to the number of adversarial queri...

• Type: Journal
• Year: 2015
• Where: ASIACRYPT
• Authors: Benoît Libert, Thomas Peters, Marc Joye, Moti Yung
• Keywords: ASIACRYPT 2015, Cryptology