Physical Review A
Differential-phase-shift quantum key distribution with phase modulation to combat sequential attacks
Hiroki Kawahara, Toru Oka, Kyo Inoue
Abstract
Phase-modulated differential-phase-shift (DPS) quantum key distribution (QKD) is presented for combating sequential attacks that most severely restrict the DPS-QKD system distance. Slow phase modulation imposed onto the DPS signal obstructs the optimum unambiguous state discrimination measurement conducted in the sequential attack and improves the QKD distance as a result. The condition with which the phase modulation does not degrade the DPS-QKD system performance is also described.