Enhancing the implementation security of quantum key distribution

The advent of quantum computers poses a severe threat to the security of our existing communication infrastructure.

Quantum Key Distribution (QKD), which bases its security on the laws of physics rather than unproven computational assumptions, has been proposed as the ultimate solution to protect the long-term security of our communications.

However, due to inevitable imperfections in the devices used to implement QKD protocols—particularly the sources—practical QKD systems suffer from security vulnerabilities that could be exploited by attackers to gain unauthorized information, thus invalidating QKD's seemingly ironclad security guarantees.Recently, the scientific community has started to address this critical issue, with initiatives aimed at both developing security proofs resistant against device imperfections, and at experimentally quantifying their magnitude.

However, these security proofs have tended to consider imperfections in isolation, and are thus unsuitable for real-world implementations suffering from multiple imperfections simultaneously.

Moreover, the existing experimental works have not focused on quantifying the specific parameters required to apply these security proofs, limiting their practical utility.In this project, we aim to significantly enhance the implementation security of QKD through two primary objectives.

The first is the development of a rigorous and robust security proof that, by integrating previous approaches, incorporates all possible device imperfections, and could thus secure practical implementations against all attacks aiming to exploit them.

The second objective is the development of source characterization tests that can measure the specific parameters needed to apply this security proof, demonstrating its ability to secure real-life implementations.

Achieving these objectives would significantly strengthen QKD's potential as a solution to ensure the long-term security of our communication infrastructure.