Exploring the Limits of Multi-Party Computation

Jincheng Zhang

This paper explores the design and implementation of distributed smart contracts leveraging the principles of Quantum Key Distribution (QKD) and Quantum Secure Multi-Party Computation (QSMPC). Traditional smart contracts are vulnerable to various attacks due to the inherent limitations of classical cryptography. This research proposes a novel architecture that integrates QKD for secure key exchange among contract participants and QSMPC for secure execution of contract logic. The core claim is that this combined approach offers a significantly enhanced level of security and reliability compared to existing smart contract systems. The underlying mechanism relies on establishing a quantum-secured channel for key distribution followed by a quantum-resistant multi-party computation protocol. We outline the technical aspects of this system, highlighting the challenges and potential solutions in building a truly quantum-safe distributed smart contract ecosystem. This work addresses a critical need for robust security in decentralized systems and paves the way for applications requiring the highest levels of trust and confidentiality.

Dominique Unruh

Lisa Kohl

Wenjun Luo, Li Xiang

The growth of the Internet has triggered tremendous opportunities for cooperative computation, where people are jointly conducting computation tasks based on the private inputs they each supply. These computations could occur between mutually untrusted parties, or even between competitors. Today, to conduct such computations, one entity must usually know the inputs from all the participants; however if nobody can be trusted enough to know all the inputs, privacy will become a primary concern. This problem is referred to as Secure Multi-party Computation Problem (SMC) in the literature. Research in the SMC area has been focusing on only a limited set of specific SMC problems, while privacy concerned cooperative computations call for SMC studies in a variety of computation domains. About the specific SMC problems, have some result [6,7,8,9,11,12,13], and all the result are concern Two-party computations. Recently, the paper of China has [23~28].

Jayavanth Shenoy, Patrick Grinaway, Shriphani Palakodety

Theodoros Kapourniotis, Elham Kashefi, Dominik Leichtle +2 more

Abstract Secure multi-party computation (SMPC) protocols allow several parties distrusting each other to collectively compute a function on their inputs, without revealing the input values. In this paper, we introduce a protocol that lifts SMPC to its quantum counterpart—secure multi-party quantum computation (SMPQC) for classical inputs and outputs—in a composable and statistically secure way, even for a single honest party. The soundness error—the maximum cheating probability of malicious parties—is shown to be proportional to the inverse of a polynomial with respect to the number of rounds in the protocol, and can be further decreased to a negligible quantity for bounded-error quantum-polynomial-time computations. Unlike previous SMPQC protocols, our proposal only requires very limited quantum resources from all but one party. In addition, the protocol exhibits some noise robustness that can facilitate small-scale implementations with near-future technologies. The protocol is based on a new technique for quantum verification that requires only the collective remote preparation of quantum states in a single plane of the Bloch sphere. To demonstrate the ability of verifying the computation with such limited clients, we uncover and use a fundamental invariance that is inherent to measurement-based quantum computing.