QUROPE Quantum Information Processing and Communication in Europe

In the recent decade, it has been discovered that QKD systems are extremely vulnerable to side-channel attacks.In particular, by exploiting the internal working knowledge of practical detectors, it is possible to bring them to an operating region whereby only certain target detectors are sensitive to detections. Crucially, the adversary can use this loophole to learn everything about the secret key without introducing any error to the quantum channel.

In the recent decade, it has been discovered that QKD systems are extremely vulnerable to side-channel attacks. In particular, by exploiting the internal working knowledge of practical detectors, it is possible to bring them to an operating region whereby only certain target detectors are sensitive to detections. Crucially, the adversary can use this loophole to learn everything about the secret key without introducing any error to the quantum channel.

In this work, the authors study position-based cryptography in the quantum setting. On the negative side, they show that if adversaries are allowed to share an arbitrarily large entangled quantum state, no secure position-verification is possible at all. On the positive side, they show that if adversaries do not share any entangled quantum state but can compute arbitrary quantum operations, secure position-verification is achievable. In models where secure positioning is achievable, it has a number of interesting applications.