Round and Computational Efficiency of Multi-party Protocols

Cryptographic protocols are the backbone of secure digital interactions, but achieving both security and efficiency is a challenging balancing act. The challenge is how to minimize computational costs and reduce interaction while maintaining provable security. This book explores cutting-edge techniques to optimize cryptographic protocols under well-established assumptions. The monograph focuses on secure multi-party computation, non-malleable commitments, and proof systems, presenting new constructions based on general and standard cryptographic assumptions. Topics and features: First optimal-round two-party computation protocol: introduces the first secure, two-party computation protocol (and multi-party protocol for coin-tossing) with black-box simulation under standard assumptions, achieving optimal round complexity in the simultaneous message exchange model Breakthrough in non-malleable commitments: develops the first four-round, concurrent, non-malleable commitment scheme based on one-way functions and a three-round variant under stronger (still general and standard) assumptions Advances in zero-knowledge proofs: non-interactive, Zero-Knowledge proof systems that improve both efficiency and generality, enhancing practical applicability in cryptographic protocols Efficient witness-indistinguishable proof systems: three-round, witness-indistinguishable proof systems with a novel delayed-input property, with application to interactive zero-knowledge This work is primarily intended for researchers, academics, and graduate students in cryptography, theoretical computer science, and cybersecurity who are interested in designing cryptographic protocols from standard and general assumptions-in particular in the setting where no setup is available.