INT-UQKD International Use cases for Operational QKD Applications and Services

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The project main objective is to develop and demonstrate international use cases for quantum key distribution (QKD) in operational IT environments. This requires the integration of space QKD and fibre-based QKD systems into a hybrid space and terrestrial network allowing to demonstrate in-the-field global testbed capabilities. The project activities include the deployment of QKD networks connecting Luxembourg, Belgium, Singapore, Canada and the United Kingdom.

RHEA System Luxembourg manages the INT-UQKD project and act as system integrator, working with POST Luxembourg, the University of Luxembourg’s SnT, HITEC Luxembourg, evolutionQ (Canada) and SpeQtral (Singapore). The project is funded through ESA’s ARTES programme and by the Singaporean Office for Space Technology & Industry.


Quantum Key Distribution (QKD) technology is expected to be the next major step in the provision of cyber-secured connectivity and security sensitive applications, as traditional cryptographic techniques are threatened by the emergence of quantum computing. The use of quantum keys makes it possible to verify the integrity of digital communications. Specially equipped fibre networks and hybrid satellite-terrestrial networks are required for long-distance communications. The key challenges reside in the interworking of all QKD devices involved in the system architecture as well as the interfacing with existing end-users’ network and infrastructure.


The definition, verification and validation of focussed use cases is expected to guide future international QKD solutions, serving notably European Union (EU) aspirations of digital sovereignty and strategic autonomy. Creating real-life operational demonstrations helps with the assessment of technology and security compliance, and with identification of future QKD policy requirements.


The following features are provided by the INT-UQKD project:

  • Global coverage through a hybrid terrestrial-space infrastructure

  • Deployment of a global test environment for QKD technology validation

  • Operability within a short period using state-of-art technology

The ultimate goal of the INT-UQKD project is to deploy and demonstrate in-field operational capability that employs Quantum Keys in existing and real-life international operational IT environments.

System Architecture

The overall high-level project architecture is shown in the figure below:

INT-UQKD system architecture


The INT-UQKD project is structured in phases.

During the initial phase, the use cases, system requirements, system architecture and interfaces are defined with a special focus on the first demonstration between Luxembourg and Belgium.

As of mid-2023 the first demonstration based on a terrestrial QKD network between Luxembourg and Belgium is deployed over an existing cross-border optical fibre. In parallel, the system design is finalised to include the space segment with SpeQtral-1, an innovative QKD satellite provided by SpeQtral. This is followed by a long distance QKD demonstration between Europe and Asia using the hybrid space and terrestrial fibre networks put in place between Belgium-Luxembourg and Singapore. Additional demonstrations with Canada and the UK are also considered.

Current status

The INT-UQKD project started in September 2022. The project activities are currently focusing on defining the use cases, system requirements and to start defining the overall system architecture in preparation of the Preliminary Design Review foreseen in September 2023.