UPPER BOUNDS ON THE PERFORMANCE OF DIFFERENTIAL-PHASE-SHIFT QUANTUM KEY DISTRIBUTION
In this paper, we investigate limitations imposed by sequential attacks on the performance of a differential-phase-shift (DPS) quantum key distribution (QKD) protocol with weak coherent pulses. Specifically, we analyze a sequential attack based on optimal unambiguous discrimination of the relative phases between consecutive signal states emitted by the Source. We show that this attack can provide tighter upper bounds for the security of a DPS QKD scheme than those derived from sequential attacks where the eavesdropper aims to identify the state of each signal emitted by the source Unambiguously.
differential-phase-shift quantum key distribution quantum key distribution sequential attack security quantum cryptography unambiguous state discrimination intercept-resend attack