Nicolas Fabre

Quantum Key Distribution (QKD) is arguably the most mature application of principles of quantum mechanics to cryptography, and several lab and field demonstrations have been realized. However the realization of QKD in deployed networks, with high distances and/or complex network architecture is still a challenge. Trusted nodes is a known solution to these issues, but requires the delegation of trust to third parties. Here, we propose a trusted node protocol where the requirements of trust delegation are lowered, with no overhead in the consumption of the key exchanged with QKD, allowing to keep the same secret key rate. This protocol is then applied to 2 links in the Parisian Quantum Network, composed of dark dedicated fibers between 8 nodes in the Parisian region, for a total fiber distance of 57 km. Our results show the overall key exchange with no degradation of the key rate.