Experimental Demonstration of Twin-Field Quantum Digital Signatures over 504 km

TL;DR

This paper demonstrates a groundbreaking twin-field quantum digital signature system over 504 km fiber, achieving record distances and high signature rates, advancing quantum cryptography's practical security applications.

Contribution

First experimental realization of twin-field quantum digital signatures over 504 km, significantly surpassing previous distance and rate benchmarks in quantum cryptography.

Findings

Maximum transmission distance of 504 km surpasses previous records by over 200 km.

Signature rate of 21.1 per second for 1 Mbit files at 302 km.

Both single-bit and multi-bit schemes outperform prior work by over two orders of magnitude.

Abstract

Digital signatures are one of the security cornerstones of the current information age. Compared with classical digital signatures based on computational complexity, quantum digital signatures (QDS) theoretically guarantee data integrity, authenticity, and non-repudiation by quantum mechanics, showing great potential for development in cryptography and thus attracting widespread attention. However, the performance of existing QDS systems are still limited in rate and distance. Here we report the first experimental demonstration of twin-field QDS (TF-QDS) using a GHz system. We achieve a maximum transmission distance of 504 km fiber spools for both single-bit and multi-bit schemes, surpassing all existing state-of-the-art QDS experiments more than 200 km. Furthermore, by combining the one-time universal hash method, we achieve a maximum signature rate of 21.1 times per second for a 1 Mbit file over fiber distances up to 302 km. In this work, the signature rates of both single-bit scheme and multi-bit scheme are more than two orders of magnitude higher than that of previous works at similar distance. Our work provides a new record for long-distance and high-rate QDS, representing a significant step in the development of QDS.