Quantum Key Distribution (QKD) and Quantum Random Number Generators (QRNGs) are two quantum technologies, operating at the single/few-photon level, that can enhance the security of communications.
Quantum Key Distribution
QKD systems are used to securely share encryption keys between two distant parties by transmitting and measuring quantum-level pulses of light transmitted through optical fibres or free space.
In discrete variable (DV) QKD systems, the transmitted pulses are at the single-photon level. The security of a QKD system is crucial to its use and depends on the protocol and the performance of the hardware with which it is implemented. Parameters that characterise the transmitted single-photon states (e.g. mean photon number per pulse, encoding accuracy, state indistinguishability) and the single-photon detection system (e.g. properties of the single-photon detectors, decoding accuracy) need to be measured to assess the security of a QKD system.
NPL has developed methods and facilities to measure security parameters relevant to fibre DV-QKD systems; we are expanding our expertise to better address fibre DV-QKD facilities (including their resilience to hacking attacks), as well as free-space/satellite DV-QKD systems, and fibre CV-QKD systems.
Quantum Random Number Generators
Random number generators (RNGs) are important for authentication and are essential components in quantum communication systems. QRNGs exploit fundamentally random quantum processes to deliver quantifiable randomness.
Statistical tests of output sequences may unmask a poor random number generator, but passing such tests cannot guarantee unpredictability of those numbers by another party. For QRNGs, stronger certification is possible than for non-quantum RNGs because the physical process used to create the output sequence can be theoretically analysed and physically tested.
NPL, in collaboration with the university of York, has developed a methodology for testing QRNGs, and is developing methods and facilities to measure key parameters relevant to various photonic device-dependant and semi-device-dependent QRNGs.
Find out more information about testing the output of a random number generator
Contact our quantum team