Random signal generation and synchronization in lab-scale measurement device independent–quantum key distribution systems

Measurement-Device-Independent Quantum Key Distribution (MDI-QKD) is a two-photon protocol devised to eliminate eavesdropping attacks that interrogate or control the detector in realized quantum key distribution systems. In MDI-QKD, the measurements are carried out by an untrusted third party, and the measurement results are announced openly. Knowledge or control of the measurement results gives the third party no information about the secret key. Error-free implementation of the MDI-QKD protocol requires the crypto-communicating parties, Alice and Bob, to independently prepare and transmit single photons that are physically indistinguishable, with the possible exception of their polarization states. In this paper, we apply the formalism of quantum optics and Monte Carlo simulations to quantify the impact of small errors in wavelength, bandwidth, polarization and timing between Alice's photons and Bob's photons on the MDI-QKD quantum bit error rate (QBER). Using published single-photon source characteristics from two-photon interference experiments as a test case, our simulations predict that the finite tolerances of these sources contribute (4.04+/-20/Nsifted) to the QBER in an MDI-QKD implementation generating an Nsifted-bit sifted key.

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Improving the Performance of Practical Quantum Key Distribution With Advantage Distillation Technology

10.21203/rs.3.rs-753036/v1 ◽

2021 ◽

Author(s):

Hong-Wei Li ◽

Chun-Mei Zhang ◽

Mu-Sheng Jiang ◽

Qing-Yu Cai

Keyword(s):

Distribution System ◽

Quantum Key Distribution ◽

Distribution Systems ◽

Key Distribution ◽

Measurement Device ◽

Transmission Distance ◽

State Measurement ◽

Quantum Step ◽

State Device ◽

Measurement Device Independent

Abstract To improve the maximal transmission distance and the maximal error rate tolerance, we apply the advantage distillation technology to analyze security of the practical decoy-sate quantum key distribution system. Based on the practical experimental parameters, the device-dependent quantum key distribution protocols and the measurement-device-independent quantum key distribution protocols have been respectively analyzed, and our analysis results demonstrate that the advantage distillation technology can significantly improve the performance of different quantum key distribution protocols. In the four-state and six-state device-dependent quantum key distribution protocols, we prove that the maximal transmission distance can be improved from 142 km to 180 km and from 146 km to 187 km respectively. In the four-state and six-state measurement-device-independent quantum key distribution protocols, we prove that the maximal transmission distance can be improved from 195 km to 273 km and from 200 km to 282 km respectively. More interestingly, the advantage distillation technology does not need to change the hardware devices about the quantum step, thus it can be conveniently to be applied in various practical quantum key distribution systems.

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Measurement-device-independent quantum key distribution with leaky sources

Scientific Reports ◽

10.1038/s41598-021-81003-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Weilong Wang ◽

Kiyoshi Tamaki ◽

Marcos Curty

Keyword(s):

Quantum Key Distribution ◽

Communication Systems ◽

Signal Transmission ◽

Information Leakage ◽

Key Distribution ◽

Time Frame ◽

Measurement Device ◽

Decoy State ◽

Unrealistic Assumption ◽

Measurement Device Independent

AbstractMeasurement-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.

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