Differential phase shift quantum secret sharing using a twin field

Abstract

Quantum secret sharing (QSS) is essential for multiparty quantum communication, which is one of cornerstones in the future quantum internet. However, a linear rate-distance limitation severely constrains the secure key rate and transmission distance of QSS. Here, we present a practical QSS protocol among three participants based on the differential phase shift scheme and twin field ideas for the solution of high-efficiency multiparty communication task. In contrast to formerly proposed differential phase shift QSS protocol, our protocol can break the linear PLOB bound, theoretically improving the secret key rate by three orders of magnitude in a 300-km-long fiber. Furthermore, the new protocol is secure against Trojan horse attacks that cannot be resisted by previous differential phase shift QSS.

Differential Phase Shift Quantum Secret Sharing Using a Twin Field with Asymmetric Source Intensities

“…In Figure 4, we plot the results of our asymmetric protocol when the total pulses are set N = 10 12 , where the difference in length between Alice's channel and Bob's is fixed at 10 km, 50 km, and 100 km, respectively. When the original TF-DPSQSS [29] protocol is applied to the asymmetric channels, a high system error rate will arise since different channel transmittances will lead to the poor performance of interference at the beam splitter. Figure 5 presents numerical results of our asymmetric protocols and the original TF-DPSQSS [29] protocol with the difference in length between two channels fixed at 10 km and 14 km.…”

“…In this section, we will discuss the security of our protocol against eavesdropping. Because of the equivalence [29] between our asymmetric protocol and differential phase shift QSS, we can apply the conclusion in differential phase shift quantum key distribution [25] to the analysis of both an external eavesdropper and an internal eavesdropper in our protocol.…”

“…Firstly, we assume that Bob is the malicious one. In this case, we have equivalence configuration [29] shown in Figure 2a. Bob wants to know Charlie's key by himself, and also needs to know Alice's modulation phase to pass the test-bit checking among Alice, Bob, and Charlie after the creation of the raw key.…”

“…Nevertheless, the linear rate-distance limitation constricts the key rate and transmission distance of QSS [27,28]. Recently, to exceed the linear bound and further enhance the practical performance of QSS, a differential phase shift quantum secret sharing (DPSQSS) protocol [29] using a twin field (TF) [30] has been proposed. Unfortunately, this protocol suffers from low key rate and short transmission distance over channels with different transmittances, which constrains its application in a practical network setting.…”

Detector‐device‐independent quantum secret sharing based on hyper‐encoding and single‐photon Bell‐state measurement

“…Recently, some verifiable QSS protocols were proposed. 22,23 Gu et al 25 proposed an experimental implementation of three-party QSS based on differential phase shift and twin field. Pinnell et al 26 gave a proof-of-principle implementation for high-dimensional QSS by exploiting the orbital angular momentum in high-dimensional Hilbert space and perfect Vortex beams.…”