Beating the fault-tolerance bound and security loopholes for Byzantine agreement with a quantum solution

Abstract

Byzantine agreement, the underlying core of blockchain, aims to make every node in a decentralized network reach consensus. Classical Byzantine agreements unavoidably face two major problems. One is $1/3$ fault-tolerance bound, which means that the system to tolerate $f$ malicious players requires at least $3f+1$ players. The other is the security loopholes from its classical cryptography methods. Here, we propose a Byzantine agreement framework with unconditional security to break this bound with nearly $1/2$ fault tolerance due to multiparty correlation provided by quantum digital signatures. \textcolor{black}{It is intriguing that quantum entanglement is not necessary to break the $1/3$ fault-tolerance bound, and we show that weaker correlation, such as asymmetric relationship of quantum digital signature, can also work.} Our work strictly obeys two Byzantine conditions and can be extended to any number of players without requirements for multiparticle entanglement. We experimentally demonstrate three-party and five-party consensus for a digital ledger. Our work indicates the quantum advantage in terms of consensus problems and suggests an important avenue for quantum blockchain and quantum consensus networks.

21 pages, 7 figures. All comments are welcome!

References in corpus (18)

• Supplementary information for "Quantum supremacy using a programmable superconducting processor"
• Breaking the Rate-Loss Bound of Quantum Key Distribution with Asynchronous Two-Photon Interference
• Experimental quantum secure network with digital signatures and encryption
• Long-Distance Measurement-Device-Independent Multiparty Quantum Communication
• Quantum digital signatures with quantum key distribution components
• Experimental demonstration of a quantum protocol for Byzantine agreement and liar detection
• Experimental quantum secret sharing based on phase encoding of coherent states
• Efficient Quantum Digital Signatures without Symmetrization Step
• Experimental Quantum Multiparty Communication Protocols
• Experimental quantum advantage with quantum coupon collector
• One-Time Universal Hashing Quantum Digital Signatures without Perfect Keys
• Experimental composable security decoy-state quantum key distribution using time-phase encoding
• Secure and practical multiparty quantum digital signatures
• Multipartite Continuous Variable Solution for the Byzantine Agreement Problem
• Multi-party Quantum Byzantine Agreement Without Entanglement
• Homodyne Detection Quadrature Phase Shift Keying Continuous-Variable Quantum Key Distribution with High Excess Noise Tolerance
• Quantum-accelerated algorithms for generating random primitive polynomials over finite fields
• Addendum to "Experimental demonstration of a quantum protocol for Byzantine agreement and liar detection" arXiv:0710.0290

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• Information-theoretically secure quantum timestamping with one-time universal hashing
• Scalable and Highly Fault-Tolerant Circular Quantum Byzantine Agreement