Finite-key security analysis of differential-phase-shift quantum key distribution
Differential-phase-shift (DPS) quantum key distribution (QKD) is one of the major QKD protocols that can be implemented with a simple setup using a laser source and a passive detection unit. Recently, an information-theoretic security proof of this protocol was established by Mizutani et al. [npj Qu...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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American Physical Society
2023-05-01
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| Series: | Physical Review Research |
| Online Access: | http://doi.org/10.1103/PhysRevResearch.5.023132 |
| _version_ | 1797210431084822528 |
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| author | Akihiro Mizutani Yuki Takeuchi Kiyoshi Tamaki |
| author_facet | Akihiro Mizutani Yuki Takeuchi Kiyoshi Tamaki |
| author_sort | Akihiro Mizutani |
| collection | DOAJ |
| description | Differential-phase-shift (DPS) quantum key distribution (QKD) is one of the major QKD protocols that can be implemented with a simple setup using a laser source and a passive detection unit. Recently, an information-theoretic security proof of this protocol was established by Mizutani et al. [npj Quantum Inf. 5, 87 (2019)2056-638710.1038/s41534-019-0194-3], assuming an infinitely large number of emitted pulses. To implement the DPS protocol in a real-life world, it is indispensable to analyze the security with the finite number of emitted pulses. The extension of the security proof to the finite-size regime requires the accommodation of the statistical fluctuations to determine the amount of privacy amplification. In doing so, Azuma's inequality is often employed, but unfortunately we show that in the case of the DPS protocol, this results in a substantially low key rate. This low key rate is due to a loose estimation of the sum of probabilities regarding three-photon emission whose probability of occurrence is very small. The main contribution of our work is to show that this obstacle can be overcome by exploiting the recently found novel concentration inequality, Kato's inequality. As a result, the key rate of the DPS protocol is drastically improved. For instance, assuming typical experimental parameters, a 3-Mbit secret key can be generated over 77 km for 8.3 hours, which shows the feasibility of DPS QKD under a realistic setup. |
| first_indexed | 2024-04-24T10:10:29Z |
| format | Article |
| id | doaj.art-38c296f9c7064461b84d2dec7b3a797e |
| institution | Directory Open Access Journal |
| issn | 2643-1564 |
| language | English |
| last_indexed | 2024-04-24T10:10:29Z |
| publishDate | 2023-05-01 |
| publisher | American Physical Society |
| record_format | Article |
| series | Physical Review Research |
| spelling | doaj.art-38c296f9c7064461b84d2dec7b3a797e2024-04-12T17:31:18ZengAmerican Physical SocietyPhysical Review Research2643-15642023-05-015202313210.1103/PhysRevResearch.5.023132Finite-key security analysis of differential-phase-shift quantum key distributionAkihiro MizutaniYuki TakeuchiKiyoshi TamakiDifferential-phase-shift (DPS) quantum key distribution (QKD) is one of the major QKD protocols that can be implemented with a simple setup using a laser source and a passive detection unit. Recently, an information-theoretic security proof of this protocol was established by Mizutani et al. [npj Quantum Inf. 5, 87 (2019)2056-638710.1038/s41534-019-0194-3], assuming an infinitely large number of emitted pulses. To implement the DPS protocol in a real-life world, it is indispensable to analyze the security with the finite number of emitted pulses. The extension of the security proof to the finite-size regime requires the accommodation of the statistical fluctuations to determine the amount of privacy amplification. In doing so, Azuma's inequality is often employed, but unfortunately we show that in the case of the DPS protocol, this results in a substantially low key rate. This low key rate is due to a loose estimation of the sum of probabilities regarding three-photon emission whose probability of occurrence is very small. The main contribution of our work is to show that this obstacle can be overcome by exploiting the recently found novel concentration inequality, Kato's inequality. As a result, the key rate of the DPS protocol is drastically improved. For instance, assuming typical experimental parameters, a 3-Mbit secret key can be generated over 77 km for 8.3 hours, which shows the feasibility of DPS QKD under a realistic setup.http://doi.org/10.1103/PhysRevResearch.5.023132 |
| spellingShingle | Akihiro Mizutani Yuki Takeuchi Kiyoshi Tamaki Finite-key security analysis of differential-phase-shift quantum key distribution Physical Review Research |
| title | Finite-key security analysis of differential-phase-shift quantum key distribution |
| title_full | Finite-key security analysis of differential-phase-shift quantum key distribution |
| title_fullStr | Finite-key security analysis of differential-phase-shift quantum key distribution |
| title_full_unstemmed | Finite-key security analysis of differential-phase-shift quantum key distribution |
| title_short | Finite-key security analysis of differential-phase-shift quantum key distribution |
| title_sort | finite key security analysis of differential phase shift quantum key distribution |
| url | http://doi.org/10.1103/PhysRevResearch.5.023132 |
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