The Info-communications Media Development Authority (IMDA) of Singapore, supported by the Telecommunications Standards Advisory Committee (TSAC), has released a draft reference specification aimed at establishing a security framework for Quantum Key Distribution Networks (QKDN). This document, Draft IMDA RS SecQKDN Issue 1 (February 2026), serves as an informative guide for the secure deployment and interoperability of quantum cryptographic infrastructure.

Overview of Proposed Standards

The specification focuses on the security architecture, risk management, and countermeasures required to ensure the resilience of QKDN implementations. It aligns with the international ITU-T X.1710 security framework and covers five logical layers:

Quantum Layer: Security of QKD modules and quantum/classical links.

Key Management Layer: Processing, storage, and relay of QKD keys.

Control Layer: Routing, session authentication, and link control.

Management Layer: Fault, configuration, and performance monitoring.

Service Layer: Interfaces for secure application entities.

Impact on Manufacturers and Stakeholders

Manufacturers of QKD modules and network equipment must consider new security baselines to ensure their devices are suitable for deployment in Singapore’s public telecommunications infrastructure. Key impacts include:

Hardware Security: Requirements for tamper-resistant hardware, such as Hardware Security Modules (HSMs), to safeguard cryptographic keys.

Physical Node Security: Recommendations for "Trusted Nodes" (TN) including electromagnetic (EM) shielding, multi-factor physical access control, and environmental sensors.

Countermeasures against Quantum Threats: Manufacturers must implement detectable anomalies for eavesdropping (e.g., monitoring Quantum Bit Error Rate - QBER) and mitigation strategies for side-channel attacks like detector blinding or Trojan-horse attacks.

Supply Chain Resilience: Increased scrutiny on hardware and firmware integrity during installation and maintenance to prevent the introduction of backdoors.

Technical Parameters and Testing Procedures

The proposed specification introduces technical expectations for the following areas:

Protocol Integrity: Adoption of IT-secure authentication and cryptographic algorithms (e.g., Wegman-Carter MAC, TLS 1.3, or IPSec) for data transfer and control links.

Optical Parameters: Use of active or passive components (isolators, filters, power meters) to reduce light injection or leakage in quantum channels.

Availability Mechanisms: Implementation of redundant instances with automatic failover and DoS mitigation tools to ensure continuous key generation.

Audit and Logging: Requirements for secure boot, audit trails, and activity logging for forensic integrity and accountability.

Permitted Radio and Optical Bands

While this specification primarily concerns optical quantum channels, it defines the security requirements for the Classical Channel used for post-processing and the Quantum Channel used for photon exchange. Manufacturers must ensure that these channels are protected against intercept-and-resend attacks and unauthorized network access via external interfaces.

Feedback and Deadlines

As this is a Draft Reference Specification, it is currently a "living document" subject to review and revision. Stakeholders, including radio device manufacturers and type approval service companies, are encouraged to review the security recommendations to prepare for future adoption by network operators. Feedback should be submitted to the IMDA via the official consultation channels specified on their website. Implementers should monitor the IMDA website for the final issuance date and any associated compliance deadlines.