The problem of perfectly secure communication has enjoyed considerable theoretical treatment over the last decades. Results in this area include the identification of multipath transmission as a necessary ingredient, ...The problem of perfectly secure communication has enjoyed considerable theoretical treatment over the last decades. Results in this area include the identification of multipath transmission as a necessary ingredient, as well as quantum key distribution （QKD）, which can perfectly protect direct lines, Combining the advantages of the quantum and multipath transmission paradigm, as well as rigorously analyzing the security of such combined techniques, is possible by virtue of game-theory. Based on a game-theoretic measure of channel vulnerability, the authors prove the problem of setting up infrastructures for QKD-based multipath transmission to be NP-complete. The authors consider the problem in two flavors, both being computationally hard. Remarkably, the authors＇ results indicate that the P-vs-NP-question is only of minor effect for confidentiality, because either nowadays public-key cryptosystems remain secure （in case that P, NP） or infrastructures facilitating perfectly confidential communication can be constructed efficiently （in case that P = NP）.展开更多
The security of quantum key distribution(QKD)is severely threatened by discrepancies between realistic devices and theoretical assumptions.Recently,a significant framework called the reference technique was proposed t...The security of quantum key distribution(QKD)is severely threatened by discrepancies between realistic devices and theoretical assumptions.Recently,a significant framework called the reference technique was proposed to provide security against arbitrary source flaws under current technology such as state preparation flaws,side channels caused by mode dependencies,the Trojan horse attacks and pulse correlations.Here,we adopt the reference technique to prove security of an efficient four-phase measurement-device-independent QKD using laser pulses against potential source imperfections.We present a characterization of source flaws and connect them to experiments,together with a finite-key analysis against coherent attacks.In addition,we demonstrate the feasibility of our protocol through a proof-of-principle experimental implementation and achieve a secure key rate of 253 bps with a 20 d B channel loss.Compared with previous QKD protocols with imperfect devices,our study considerably improves both the secure key rate and the transmission distance,and shows application potential in the practical deployment of secure QKD with device imperfections.展开更多
Telecom-band polarization-entangled photon- pair source has been widely used in quantum communi- cation due to its acceptable transmission loss. It is also used in cooperation with wavelength-division multiplexing （...Telecom-band polarization-entangled photon- pair source has been widely used in quantum communi- cation due to its acceptable transmission loss. It is also used in cooperation with wavelength-division multiplexing （WDM） to construct entanglement distributor. However, previous schemes generally are not suitable for multinode scenario. In this paper, we construct a telecom-band po- larization-entangled photon-pair source, and it shows ul- trahigh fidelity and concurrence which are both greater than 90 % （raw data）. Moreover, we set up a four-by-four entanglement distributor based on WDM. We check the 16 Clauser-Horne-Shimony-Holt inequalities, which show nonlocality. Lastly, as an example of practical application of this source, we estimate the quantum bit error rates and quantum secret key rates when it is used in quantum key distribution. Furthermore, the transmission of entanglement in long optical fibers is also demonstrated.展开更多
Considering the air-water interface and ocean water’s optical attenuation,the performance of quantum key distribution(QKD)based on air-water channel is studied.The effects of photons’various incident angles to air-w...Considering the air-water interface and ocean water’s optical attenuation,the performance of quantum key distribution(QKD)based on air-water channel is studied.The effects of photons’various incident angles to air-water interface on quantum bit error rate(QBER)and the maximum secure transmission distance are analyzed.Taking the optical attenuation of ocean water into account,the performance bounds of QKD in different types of ocean water are discussed.The simulation results show that the maximum secure transmission distance of QKD gradually reduces as the incident angle from air to ocean water increases.In the clearest ocean water with the lowest attenuation,the maximum secure transmission distance of photons far exceeds the the working depth of underwater vehicles.In intermediate and murky ocean waters with higher attenuation,the secure transmission distance shortens,but the underwater vehicle can deploy other accessorial methods for QKD with perfect security.So the implementation of OKD between the satellite and the underwater vehicle is feasible.展开更多
文摘The problem of perfectly secure communication has enjoyed considerable theoretical treatment over the last decades. Results in this area include the identification of multipath transmission as a necessary ingredient, as well as quantum key distribution （QKD）, which can perfectly protect direct lines, Combining the advantages of the quantum and multipath transmission paradigm, as well as rigorously analyzing the security of such combined techniques, is possible by virtue of game-theory. Based on a game-theoretic measure of channel vulnerability, the authors prove the problem of setting up infrastructures for QKD-based multipath transmission to be NP-complete. The authors consider the problem in two flavors, both being computationally hard. Remarkably, the authors＇ results indicate that the P-vs-NP-question is only of minor effect for confidentiality, because either nowadays public-key cryptosystems remain secure （in case that P, NP） or infrastructures facilitating perfectly confidential communication can be constructed efficiently （in case that P = NP）.
基金supported by the Natural Science Foundation of Jiangsu Province(BK20211145)the Fundamental Research Funds for the Central Universities(020414380182)+1 种基金the Key Research and Development Program of Nanjing Jiangbei New Aera(ZDYD20210101)the Program for Innovative Talents and Entrepreneurs in Jiangsu(JSSCRC2021484)。
文摘The security of quantum key distribution(QKD)is severely threatened by discrepancies between realistic devices and theoretical assumptions.Recently,a significant framework called the reference technique was proposed to provide security against arbitrary source flaws under current technology such as state preparation flaws,side channels caused by mode dependencies,the Trojan horse attacks and pulse correlations.Here,we adopt the reference technique to prove security of an efficient four-phase measurement-device-independent QKD using laser pulses against potential source imperfections.We present a characterization of source flaws and connect them to experiments,together with a finite-key analysis against coherent attacks.In addition,we demonstrate the feasibility of our protocol through a proof-of-principle experimental implementation and achieve a secure key rate of 253 bps with a 20 d B channel loss.Compared with previous QKD protocols with imperfect devices,our study considerably improves both the secure key rate and the transmission distance,and shows application potential in the practical deployment of secure QKD with device imperfections.
基金This work was supported by the National Nat- ural Science Foundation of China （61327901, 61490711, 11274289, 11325419, 11374288 and 11104261）, the National Basic Research Program of China （2011CB921200）, the Strategic Priority Research Program （B） of the Chinese Academy of Sciences （XDB01030300）, the National Science Ftmd for Distinguished Young Scholars （61225025）, and the Fundamental Research Funds for Central Universities （WK2470000011）.
文摘Telecom-band polarization-entangled photon- pair source has been widely used in quantum communi- cation due to its acceptable transmission loss. It is also used in cooperation with wavelength-division multiplexing （WDM） to construct entanglement distributor. However, previous schemes generally are not suitable for multinode scenario. In this paper, we construct a telecom-band po- larization-entangled photon-pair source, and it shows ul- trahigh fidelity and concurrence which are both greater than 90 % （raw data）. Moreover, we set up a four-by-four entanglement distributor based on WDM. We check the 16 Clauser-Horne-Shimony-Holt inequalities, which show nonlocality. Lastly, as an example of practical application of this source, we estimate the quantum bit error rates and quantum secret key rates when it is used in quantum key distribution. Furthermore, the transmission of entanglement in long optical fibers is also demonstrated.
基金supported by the National High Technology Research and Development Program of China(No.2011AA7014061)
文摘Considering the air-water interface and ocean water’s optical attenuation,the performance of quantum key distribution(QKD)based on air-water channel is studied.The effects of photons’various incident angles to air-water interface on quantum bit error rate(QBER)and the maximum secure transmission distance are analyzed.Taking the optical attenuation of ocean water into account,the performance bounds of QKD in different types of ocean water are discussed.The simulation results show that the maximum secure transmission distance of QKD gradually reduces as the incident angle from air to ocean water increases.In the clearest ocean water with the lowest attenuation,the maximum secure transmission distance of photons far exceeds the the working depth of underwater vehicles.In intermediate and murky ocean waters with higher attenuation,the secure transmission distance shortens,but the underwater vehicle can deploy other accessorial methods for QKD with perfect security.So the implementation of OKD between the satellite and the underwater vehicle is feasible.
