A pioneering chip-based quantum digital signature (QDS) network achieves secure document signing over 200 km of fiber, leveraging integrated photonics to miniaturize transmitters and centralize measurement systems.This breakthrough paves the way for future scalable, cost-effective, and robust quantum-secure communication networks.
The development of quantum networks is paramount towards practical and secure communications. Quantum digital signatures (QDS) offer an information-theoretically secure solution for ensuring data integrity, authenticity, and non-repudiation, rapidly growing from proof-of-concept to robust demonstrations. However, previous QDS systems relied on expensive and bulky optical equipment, limiting large-scale deployment and reconfigurable networking construction. Here, we introduce and verify a chip-based QDS network, placing the complicated and expensive measurement devices in the central relay while each user needs only a low-cost transmitter. We demonstrate the network with a three-node setup using an integrated encoder chip and decoder chip. By developing a 1-decoy-state one-time universal hash-QDS protocol, we achieve a maximum signature rate of 0.0414 times per second for a 1 Mbit file over fiber distances up to 200 km, surpassing all current state-of-the-art QDS experiments. This study validates the feasibility of chip-based QDS, paving the way for large-scale deployment and integration with existing fiber infrastructure.
The development of quantum networks is paramount towards practical and secure communications. Quantum digital signatures (QDS) offer an information-theoretically secure solution for ensuring data integrity, authenticity, and non-repudiation, rapidly growing from proof-of-concept to robust demonstrations. However, previous QDS systems relied on expensive and bulky optical equipment, limiting large-scale deployment and reconfigurable networking construction. Here, we introduce and verify a chip-based QDS network, placing the complicated and expensive measurement devices in the central relay while each user needs only a low-cost transmitter. We demonstrate the network with a three-node setup using an integrated encoder chip and decoder chip. By developing a 1-decoy-state one-time universal hashing-QDS protocol, we achieve a maximum signature rate of 0.0414 times per second for a 1 Mbit messages over fiber distances up to 200 km, surpassing all current state-of-the-art QDS experiments. This study validates the feasibility of chip-based QDS, paving the way for large-scale deployment and integration with existing fiber infrastructure.
Quantum digital signature (QDS) is an approach to guarantee the nonrepudiation, unforgeability, and transferability of a signature with information-theoretical security. Previous experimental realizations of QDS relied on an unrealistic assumption of secure channels and the longest distance is several kilometers. Here, we have experimentally demonstrated a recently proposed QDS protocol without assuming any secure channel. Exploiting the decoy state modulation, we have successfully signed a one-bit message through an up to 102-km optical fiber. Furthermore, we continuously run the system to sign the longer message ``USTC'' with 32 bits at the distance of 51 km. Our results pave the way towards the practical application of QDS.
The convergence of classical and quantum Internet technologies promises to revolutionize communication networks by leveraging the unique properties of quantum mechanics. Already today, several efforts on quantum key distribution, post-quantum cryptography, and systems-on-chip are paving the way for a seamless and secure quantum-classical hybrid Internet. We explore the role of integrated photonics on-chip systems that generate entangled photon pairs, a critical component for quantum communication. We review how integrated photonics and associated techniques can generate and manipulate photon pairs with the prospect of miniaturization and scalability. In addition, we discuss the challenges and solutions in integrating these quantum systems with existing classical Internet infrastructure, highlighting recent advances and future directions.
We propose an entanglement-based quantum digital signature (QDS) protocol optimized for quantum networks. The protocol follows the Lamport-inspired QDS paradigm but eliminates QKD post-processing by signing and verifying with raw conclusive keys, thereby reducing latency and implementation complexity. We provide a finite-size security analysis of robustness, unforgeability, and non-repudiation. Under standard fiber-loss and detector models, simulations show a consistent signature rate advantage over a representative Lamport-inspired QDS baseline across metro-to-regional distances. The proposed protocol is practical for near-term deployment while preserving end-to-end, finite key security guarantees.