ITU outlines protocols for quantum key distribution

One of the latest additions to quantum communications standards from the International Telecommunication Union (ITU) provides guidance on protocols for quantum key distribution (QKD), a means of enabling secure encryption as quantum technologies outstrip the capabilities of earlier cryptography.

The ITU standard X.1711 (Framework of QKD protocols in QKD networks) is the first-ever international standard on QKD protocols, coming more than four decades after the first QKD protocol was proposed in 1984. It adds to ITU’s standards for QKD networking and security, which support quantum-safe communications across the large-scale networks that underpin today’s global communications.

Rather than defining one specific protocol, the X.1711 standard specifies what all QKD protocols share, the common architecture they need, and the operational workflow to keep information safe from quantum-level attacks. It also explains theoretical security proofs, new security models, and related concepts.

Developed by ITU-T Study Group 17 (Security), X.1711 provides a primary reference for QKD security certification as countries and organizations consider various modules. It also aims to guide future standards.

Ultimately, the standard can help select a certified QKD module and keep information and transactions secure in the quantum age.

From standards to deployment

ITU’s standards work is closely linked to testbeds where QKD is being put into practice around the globe.

Singapore’s National Quantum-Safe Network (NQSN) Testbed, for example, works closely with ITU-T Study Group 17 on QKD-related standardization issues. In a nod to this contribution, the NQSN team was recently named a runner up in the Digital Frontiers category of the Digital@UNGA 2026 Awards organized by ITU and the United Nations Development Programme (UNDP).

ITU has worked on standards for QKD networks since 2018, with protocol aspects addressed by ITU-T Study Group 11 (Protocols, testing and combating counterfeiting) and architecture-related aspects by ITU-T Study Group 13 (Future networks), while core security aspects remain with ITU-T Study Group 17.

Building on X.1711, future ITU standards could specify particular QKD protocols in detail. ITU’s work on certification complements guidance from other bodies, such as the European Telecommunications Standards Institute (ETSI), with a widely recognized protection profile for QKD modules, and the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC), with their joint ISO/IEC standard on security requirements and testing and evaluation methods for QKD.

Reaching worldwide and beyond

A growing field for ITU is satellite-based QKD, which can extend secure key distribution over long distances. Study Group 13 is devising the necessary network architecture while Study Group 17 prepares a technical report on security considerations.

Many organizations are either establishing quantum standards or contributing to related processes. To help coordinate all these streams, ITU maintains a public database of quantum standards.

The global database forms part of ITU’s online standards landscape tool.

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