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Start Over Author "Kiyoshi Tamaki" Journal scientific reports
5 results on '"Kiyoshi Tamaki"'

1. Measurement-device-independent quantum key distribution with leaky sources

Author

Weilong Wang, Kiyoshi Tamaki, and Marcos Curty

Subjects
Medicine, Science
Abstract

Abstract Measurement-device-independent quantum key distribution (MDI-QKD) can remove all detection side-channels from quantum communication systems. The security proofs require, however, that certain assumptions on the sources are satisfied. This includes, for instance, the requirement that there is no information leakage from the transmitters of the senders, which unfortunately is very difficult to guarantee in practice. In this paper we relax this unrealistic assumption by presenting a general formalism to prove the security of MDI-QKD with leaky sources. With this formalism, we analyze the finite-key security of two prominent MDI-QKD schemes—a symmetric three-intensity decoy-state MDI-QKD protocol and a four-intensity decoy-state MDI-QKD protocol—and determine their robustness against information leakage from both the intensity modulator and the phase modulator of the transmitters. Our work shows that MDI-QKD is feasible within a reasonable time frame of signal transmission given that the sources are sufficiently isolated. Thus, it provides an essential reference for experimentalists to ensure the security of implementations of MDI-QKD in the presence of information leakage.

Published
2021
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2. Experimental demonstration of quantum digital signatures over 43 dB channel loss using differential phase shift quantum key distribution

Author

Robert J. Collins, Ryan Amiri, Mikio Fujiwara, Toshimori Honjo, Kaoru Shimizu, Kiyoshi Tamaki, Masahiro Takeoka, Masahide Sasaki, Erika Andersson, and Gerald S. Buller

Subjects
Medicine, Science
Abstract

Abstract Ensuring the integrity and transferability of digital messages is an important challenge in modern communications. Although purely mathematical approaches exist, they usually rely on the computational complexity of certain functions, in which case there is no guarantee of long-term security. Alternatively, quantum digital signatures offer security guaranteed by the physical laws of quantum mechanics. Prior experimental demonstrations of quantum digital signatures in optical fiber have typically been limited to operation over short distances and/or operated in a laboratory environment. Here we report the experimental transmission of quantum digital signatures over channel losses of up to 42.8 ± 1.2 dB in a link comprised of 90 km of installed fiber with additional optical attenuation introduced to simulate longer distances. The channel loss of 42.8 ± 1.2 dB corresponds to an equivalent distance of 134.2 ± 3.8 km and this represents the longest effective distance and highest channel loss that quantum digital signatures have been shown to operate over to date. Our theoretical model indicates that this represents close to the maximum possible channel attenuation for this quantum digital signature protocol, defined as the loss for which the signal rate is comparable to the dark count rate of the detectors.

Published
2017
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3. Security of six-state quantum key distribution protocol with threshold detectors

Author

Kiyoshi Tamaki and Go Kato

Subjects
Key generation, Quantum Physics, Multidisciplinary, Theoretical computer science, Computer science, Detector, FOS: Physical sciences, Quantum key distribution, Mathematical proof, 01 natural sciences, Article, 010305 fluids & plasmas, Computer engineering, 0103 physical sciences, Bit error rate, State (computer science), 010306 general physics, Quantum Physics (quant-ph), BB84, Protocol (object-oriented programming), Computer Science::Cryptography and Security
Abstract

We prove the unconditional security of the six-state protocol with threshold detectors and one-way classical communication. Unlike the four-state protocol (BB84), it has been proven that the squash operator for the six-state does not exist, i.e., the statistics of the measurements cannot be obtained via measurement on qubits. We propose a technique to determine which photon number states are important, and we consider a fictitious measurement on a qubit, which is defined through the squash operator of BB84, for the better estimation of Eve's information. As a result, we prove that the bit error rate threshold for the six-state protocol (12.611%) remains almost the same as the one of the qubit-based six-state protocol (12.619%). This clearly demonstrates the robustness of the six-state protocol against the use of the practical devices., Comment: 4 pages, 2 figures

Published
2016

4. Correction: Corrigendum: Measurement-device-independent quantum key distribution for Scarani-Acin-Ribordy-Gisin 04 protocol

Author

Kiyoshi Tamaki, Akihiro Mizutani, Rikizo Ikuta, Nobuyuki Imoto, and Takashi Yamamoto

Subjects
Protocol (science), Key generation, Multidisciplinary, SARG04, Computer science, Event (computing), Distributed computing, Key (cryptography), Measure (physics), Quantum key distribution, Corrigenda, Algorithm, BB84
Abstract

The measurement-device-independent quantum key distribution (MDI QKD) was proposed to make BB84 completely free from any side-channel in detectors. Like in prepare & measure QKD, the use of other protocols in MDI setting would be advantageous in some practical situations. In this paper, we consider SARG04 protocol in MDI setting. The prepare & measure SARG04 is proven to be able to generate a key up to two-photon emission events. In MDI setting we show that the key generation is possible from the event with single or two-photon emission by a party and single-photon emission by the other party, but the two-photon emission event by both parties cannot contribute to the key generation. On the contrary to prepare & measure SARG04 protocol where the experimental setup is exactly the same as BB84, the measurement setup for SARG04 in MDI setting cannot be the same as that for BB84 since the measurement setup for BB84 in MDI setting induces too many bit errors. To overcome this problem, we propose two alternative experimental setups, and we simulate the resulting key rate. Our study highlights the requirements that MDI QKD poses on us regarding with the implementation of a variety of QKD protocols.

Published
2014

5. Measurement-device-independent quantum key distribution for Scarani-Acin-Ribordy-Gisin 04 protocol

Author

Kiyoshi Tamaki, Nobuyuki Imoto, Akihiro Mizutani, Takashi Yamamoto, and Rikizo Ikuta

Subjects
Protocol (science), Key generation, Quantum Physics, Multidisciplinary, SARG04, Event (computing), Computer science, Measure (physics), FOS: Physical sciences, Quantum key distribution, Article, Computer engineering, Key (cryptography), Quantum Physics (quant-ph), BB84
Abstract

The measurement-device-independent quantum key distribution (MDI QKD) was proposed to make BB84 completely free from any side-channel in detectors. Like in prepare & measure QKD, the use of other protocols in MDI setting would be advantageous in some practical situations. In this paper, we consider SARG04 protocol in MDI setting. The prepare & measure SARG04 is proven to be able to generate a key up to two-photon emission events. In MDI setting we show that the key generation is possible from the event with single or two-photon emission by a party and single-photon emission by the other party, but the two-photon emission event by both parties cannot contribute to the key generation. On the contrary to prepare & measure SARG04 protocol where the experimental setup is exactly the same as BB84, the measurement setup for SARG04 in MDI setting cannot be the same as that for BB84 since the measurement setup for BB84 in MDI setting induces too many bit errors. To overcome this problem, we propose two alternative experimental setups, and we simulate the resulting key rate. Our study highlights the requirements that MDI QKD poses on us regarding with the implementation of a variety of QKD protocols., 15 pages, 10 figures

Published
2014

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