Abstract
Unlike traditional communication, quantum key distribution (QKD) can reach unconditional security and thus attracts intensive studies. Among all existing QKD protocols, round-robin-differential-phase-shift (RRDPS) protocol can be running without monitoring signal disturbance, which significantly simplifies its flow and improves its tolerance of error rate. Although several security proofs of RRDPS have been given, a tight finite-key analysis with a practical phase-randomized source is still missing. In this paper, we propose an improved security proof of RRDPS against the most general coherent attack based on the entropic uncertainty relation. What’s more, with the help of Azuma’s inequality, our proof can tackle finite-key effects primely. The proposed finite-key analysis keeps the advantages of phase randomization source and indicates experimentally acceptable numbers of pulses are sufficient to approach the asymptotical bound closely. The results shed light on practical QKD without monitoring signal disturbance.
Highlights
As the maturest field of quantum information sciences, quantum key distribution (QKD)[1] is well-known for its information-theoretic security
Note that the entropic uncertainty relation has been applied to BB8415, MDI16 and even TF17 protocol, not to RRDPS yet, our analysis shows that it’s doubtlessly feasible to use this technique in RRDPS
(8) DISCUSSION From the results of simulations, we can see that the larger the value of L, the more emitted pulses needed
Summary
As the maturest field of quantum information sciences, quantum key distribution (QKD)[1] is well-known for its information-theoretic security. Since the BB841 protocol was proposed, more and more QKD protocols sprang up, such as device-independent (DI)[2] protocol, measurement-deviceindependent (MDI)[3] protocol and twin-field (TF)[4] protocol. In most of these protocols, estimating Eve’s information is dependent on monitoring signal disturbance, e.g., information leakage in BB84 is a function of the error rate of sifted key bits. 2014, Toshihiko Sasaki et al proposed an exceptional protocol, named round-robin-differential-phase-shift (RRDPS)[5], which can upper bound Eve’s information without using any parameter of signal disturbance. The verification of RRDPS has been completed in several experiments[6,7,8,9]
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