Cassey C. Liang

We present the strategic framework and technical foundations behind the development of the National Quantum-Safe Network (NQSN) in Singapore—a resilient, fully interoperable quantum-safe network. The testbed features a star-topology architecture built on production-grade fiber infrastructure, supporting multi-protocol quantum key distribution (QKD) and diverse applications from multiple vendors. A centralised key and network management system underpins its interoperability, enabling seamless integration across technologies. We further explore a range of quantum-secured use cases, including data center connectivity, edge computing, hybrid QKD–post-quantum cryptography (PQC) encryption, and multi-layer integration within the OSI stack. These technical insights demonstrate the feasibility and flexibility of deploying quantum-safe capabilities in a multi-input, multi-output network environment.

The National Quantum-Safe Network (NQSN) in Singapore is a nationwide collaborative platform and a field-deployed test-bed aimed at demonstrating quantum-safe cryptography solutions. NQSN links up academic, public and private members, targets trials for quantum key distribution (QKD) network with different QKD protocols, post-quantum cryptography (PQC) and classical symmetric key technologies.