Learnt Attacks on Quantum Key Distribution under Channel Noise and Device Drift
The study investigates how an eavesdropper can gain maximum information by adapting her strategy round-to-round against a quantum key distribution channel that drifts over time. By modeling this as a constrained Markov decision process, the authors found that adaptive eavesdropping significantly increases the attacker's extracted information—by about 2.6 times in one case—compared to using a fixed circuit.