Measurement-device-independent entanglement-based quantum key distribution

We present a quantum key distribution protocol in a model in which the legitimate users gather statistics as in the measurement-device-independent entanglement witness to certify the sources and the measurement devices. We show that the task of measurement-device-independent quantum communication can be accomplished based on monogamy of entanglement, and it is fairly loss tolerate including source and detector flaws. We derive a tight bound for collective attacks on the Holevo information between the authorized parties and the eavesdropper. Then with this bound, the final secret key rate with the source flaws can be obtained. The results show that long-distance quantum cryptography over 144 km can be made secure using only standard threshold detectors.

Figure 1

Secret key rate (per sifted key bit) given by Eq. (6). We consider the following experimental parameters: $\eta =0.1$, $d={10}^{-5}$ per pulse, $\alpha =0.2$ dB/km. For simulation purposes, a secret key rate in the standard scenario is illustrated. However, in practice, the flawed sources and misaligned optical system are used. Therefore, the final key rate will be necessarily lower than what is presented in the current figure.