Secure and practical Quantum Digital Signatures

2025-08-07

AI Summary

Quantum computing poses a severe threat to classical digital signature schemes. Method: This paper proposes an information-theoretically secure quantum-resistant digital signature scheme. It constructs a practical signing protocol leveraging pre-shared keys generated via quantum key distribution, combined with universal hash families and information-theoretically secure authentication. For the first time, it provides a rigorous information-theoretic security proof under a realistic model permitting authentication failures, and systematically rectifies three critical security flaws in prior protocols. Contributions: (1) Theoretically, it establishes the first failure-tolerant information-theoretic security framework; (2) Practically, it significantly reduces pre-shared bit consumption and signature length through parameter optimization, enhancing signing efficiency; (3) Implementation-wise, it delivers an optimal protocol configuration that jointly ensures information-theoretic security, practical deployability, and quantum resistance.

Technology Category

• Machine Learning: Quantum Machine Learning
• Search and Optimization: Distributed Search
• Data Mining & Knowledge Management: Representing, Reasoning, and Using Provenance, Trust

Application Category

• Security and Privacy: Large-scale security measurements
• Responsible Web: Data and user privacy-enhancing technologies for the Web
• User Modeling, Personalization and Recommendation: Attacks and countermeasures in recommendation systems

Abstract

Digital signatures represent a crucial cryptographic asset that must be protected against quantum adversaries. Quantum Digital Signatures (QDS) can offer solutions that are information-theoretically (IT) secure and thus immune to quantum attacks. In this work, we analyze three existing practical QDS protocols based on preshared secure keys (e.g., established with quantum key distribution) and universal hashing families. For each protocol, we make amendments to close potential loopholes and prove their IT security while accounting for the failure of IT-secure authenticated communication. We then numerically optimize the protocol parameters to improve efficiency in terms of preshared bit consumption and signature length, allowing us to identify the most efficient protocol.

Problem

• Secure Quantum Digital Signatures against quantum adversaries
• Amend and prove IT security of QDS protocols
• Optimize QDS protocols for efficiency and performance

Innovation

• Amend QDS protocols for IT security
• Optimize parameters for efficiency
• Use preshared keys and hashing