Considering the fact that quantum key distribution(QKD) require dark fiber, but laying new fiber or using an dedicated fiber for QKD may not be possible in all instance, a pratical situations consider where multiplexing involving the quantum channel required for DPS QKD and the classical situation present in the same fiber is done. Such a practical situation is realised experimentally to reveal that there exists trade off between classical data rate and secure key rate obtained by the QKD protocol. The existence of this trade-off indicates that in the above situation where quantum and classical channel coexists in a fiber or telecom operator would require to optimize classical channel power, channel separation and our results indicate that an operator will need to optimize in terms of classical channel power, channel separation, and number of channels to achieve a substantial key rate and data rate while operating over filled C and $\text{C}+\text{L}$ Band scenarios.Considering the fact that quantum key distribution(QKD) require dark fiber, but laying new fiber or using an dedicated fiber for QKD may not be possible in all instance, a pratical situations consider where multiplexing involving the quantum channel required for DPS QKD and the classical situation present in the same fiber is done. Such a practical situation is realised experimentally to reveal that there exists trade off between classical data rate and secure key rate obtained by the QKD protocol. The existence of this trade-off indicates that in the above situation where quantum and classical channel coexists in a fiber or telecom operator would require to optimize classical channel power, channel separation and our results indicate that an operator will need to optimize in terms of classical channel power, channel separation, and number of channels to achieve a substantial key rate and data rate while operating over filled C and $\text{C}+\text{L}$ Band scenarios.

IEEE International Conference on Advanced Networks and Telecommunications SystemsDec 15, 20240 citations

Differential-phase-shift quantum-key-distribution protocol with a small number of random delays

Yuki Hatakeyama, Akihiro Mizutani, Go Kato +2 more

The differential-phase-shift (DPS) quantum-key-distribution (QKD) protocol was proposed aiming at simple implementation, but it can tolerate only a small disturbance in a quantum channel. The round-robin DPS (RRDPS) protocol could be a good solution for this problem, which in fact can tolerate even up to $50%$ of a bit error rate. Unfortunately, however, such a high tolerance can be achieved only when we compromise the simplicity, i.e., Bob's measurement must involve a large number of random delays ( $|\mathcal{R}|$ denotes its number), and in a practical regime of $|\mathcal{R}|$ being small, the tolerance is low. In this paper, we propose a DPS protocol to achieve a higher tolerance than the one in the original DPS protocol, in which the measurement setup is less demanding than the one of the RRDPS protocol for the high tolerance regime. We call our protocol the small-number-random DPS (SNRDPS) protocol, and in this protocol, we add only a small amount of randomness to the original DPS protocol, i.e., $2\ensuremath{\le}|\mathcal{R}|\ensuremath{\le}10$. In fact, we found that the performance of the SNRDPS protocol is significantly enhanced over the original DPS protocol only by employing a few additional delays such as $|\mathcal{R}|=2$ . Also, we found that the key generation rate of the SNRDPS protocol outperforms the RRDPS protocol without monitoring the bit error rate when it is less than $5%$ and $|\mathcal{R}|\ensuremath{\le}10$. Our protocol is an intermediate protocol between the original DPS protocol and the RRDPS protocol, and it increases the variety of the DPS-type protocols with quantified security.The differential-phase-shift (DPS) quantum-key-distribution (QKD) protocol was proposed aiming at simple implementation, but it can tolerate only a small disturbance in a quantum channel. The round-robin DPS (RRDPS) protocol could be a good solution for this problem, which in fact can tolerate even up to $50%$ of a bit error rate. Unfortunately, however, such a high tolerance can be achieved only when we compromise the simplicity, i.e., Bob's measurement must involve a large number of random delays ($|\mathcal{R}|$ denotes its number), and in a practical regime of $|\mathcal{R}|$ being small, the tolerance is low. In this paper, we propose a DPS protocol to achieve a higher tolerance than the one in the original DPS protocol, in which the measurement setup is less demanding than the one of the RRDPS protocol for the high tolerance regime. We call our protocol the small-number-random DPS (SNRDPS) protocol, and in this protocol, we add only a small amount of randomness to the original DPS protocol, i.e., $2\ensuremath{\le}|\mathcal{R}|\ensuremath{\le}10$. In fact, we found that the performance of the SNRDPS protocol is significantly enhanced over the original DPS protocol only by employing a few additional delays such as $|\mathcal{R}|=2$. Also, we found that the key generation rate of the SNRDPS protocol outperforms the RRDPS protocol without monitoring the bit error rate when it is less than $5%$ and $|\mathcal{R}|\ensuremath{\le}10$. Our protocol is an intermediate protocol between the original DPS protocol and the RRDPS protocol, and it increases the variety of the DPS-type protocols with quantified security.

arXiv:1702.00162Physical Review AApr 3, 201730 citations

Practical DPS-QKD distance limited by sequential attacl

Akira Oka

The Japan Society of Applied PhysicsJul 4, 20130 citations

Differential-phase-shift quantum key distribution with intense decoy pulses

Kyo Inoue, Toshimori Honjo

In quantum key distribution (QKD), eavesdropping is generally detected based on bit errors resulting from eavesdropper attacks. This study proposes a QKD scheme for detecting eavesdropping based on the photon-detection rate instead of the bit error rate. The differential-phase-shift (DPS) QKD protocol, which transmits lasting weak coherent pulses, is modified such that decoy pulses with a large mean photon number are randomly inserted into a signal pulse sequence. With this modification, eavesdropping can be detected by monitoring the photon-detection rates at the time slots around the decoy pulses. The key-creation performance of the modified DPS-QKD system is evaluated, and the results indicate that the QKD distance is increased with the modification.In quantum key distribution (QKD), eavesdropping is generally detected based on bit errors resulting from eavesdropper attacks. This study proposes a QKD scheme for detecting eavesdropping based on the photon-detection rate instead of the bit error rate. The differential-phase-shift (DPS) QKD protocol, which transmits lasting weak coherent pulses, is modified such that decoy pulses with a large mean photon number are randomly inserted into a signal pulse sequence. With this modification, eavesdropping can be detected by monitoring the photon-detection rates at the time slots around the decoy pulses. The key-creation performance of the modified DPS-QKD system is evaluated, and the results indicate that the QKD distance is increased with the modification.

Journal of the Optical Society of America BAug 7, 20251 citation

A comparative analysis of error correction techniques used for QKD protocols

Neha Sharma, Vikas Saxena

Journal of OpticsJul 7, 20251 citation

\text{C}+\text{L}

Band scenarios.

50%

of a bit error rate. Unfortunately, however, such a high tolerance can be achieved only when we compromise the simplicity, i.e., Bob's measurement must involve a large number of random delays (

|\mathcal{R}|

denotes its number), and in a practical regime of

|\mathcal{R}|

being small, the tolerance is low. In this paper, we propose a DPS protocol to achieve a higher tolerance than the one in the original DPS protocol, in which the measurement setup is less demanding than the one of the RRDPS protocol for the high tolerance regime. We call our protocol the small-number-random DPS (SNRDPS) protocol, and in this protocol, we add only a small amount of randomness to the original DPS protocol, i.e., $2\ensuremath{\le}|\mathcal{R}|\ensuremath{\le}10$. In fact, we found that the performance of the SNRDPS protocol is significantly enhanced over the original DPS protocol only by employing a few additional delays such as

|\mathcal{R}|=2

. Also, we found that the key generation rate of the SNRDPS protocol outperforms the RRDPS protocol without monitoring the bit error rate when it is less than

5%

and $|\mathcal{R}|\ensuremath{\le}10$. Our protocol is an intermediate protocol between the original DPS protocol and the RRDPS protocol, and it increases the variety of the DPS-type protocols with quantified security.