The End-to-End Quantum-Secured System (E2EQSS) project was initiated to explore how quantum communication technologies can be integrated into Europe’s secure connectivity infrastructure. While several quantum key distribution (QKD) solutions already exist, there was no unified framework capable of demonstrating their interoperability, scalability, and resilience in realistic network conditions. E2EQSS was designed with the dual aim of validating post-quantum security mechanisms and establishing the organisational and technological baselines necessary for their operational deployment. Key aspects included ensuring seamless integration with existing infrastructures, addressing synchronisation and performance constraints, and providing a trusted environment for evaluating quantum and classical hybrid security solutions. The activity encompassed the following tasks:
Assessment of existing secure connectivity infrastructures and their readiness for quantum technologies
Benchmarking of available QKD solutions and evaluation of their integration potential with terrestrial and satellite networks
Definition of architectural requirements for an interoperable, end-to-end quantum-secured system
Development of protocols and interfaces supporting quantum and post-quantum key management for multi-domain use cases
Implementation of pilot demonstrators to validate hybrid security frameworks in realistic operational conditions
Identification of gaps, risks, and recommendations for standardisation and future deployment
The results of this activity:
Provided a validated architecture for integrating QKD into European secure connectivity services
Demonstrated interoperability between different quantum and classical security components
Enhanced resilience against quantum-era threats by combining QKD with post-quantum cryptography
Supported Europe’s strategic autonomy in secure communications
Delivered key insights and a roadmap towards large-scale operational adoption of quantum-secured infrastructures
