Quantum key distribution with single-particle and Bell state

Gan Gao

Hao-Nan Liu, Xiang-Qian Liang, Dong‐Huan Jiang +2 more

Hao Yuan, Jun Song, Lian-Fang Han +2 more

Leilei Li, Jian Li, Yan Zuo Chang +2 more

Zhanjun Zhang, Zhong‐Xiao Man, Shi Shou-Hua

We propose a quantum key distribution (QKD) scheme in which four parties can simultaneously share a secret key via optical device. The participants divide the communication into two modes, namely, detecting mode and message mode. Taking advantage of controlled secret short key technology, the participants together can achieve the detecting mode or the message mode by switching between their two sets of optical devices. In the detecting mode, the key distributer Alice utilizes a single-photon state resource and two beam splitters and the other three participants Bob, Charlie and Dick use first-type devices to detect the superposition of vacuum and single-particle states. Hence, any eavesdropping can be found by using a variant of Bell's inequality. In the message mode, Alice uses a two-photon Bell-state resource and two polarization beam splitters instead of the single-particle state resource and beam splitters used in the detecting mode and the other three participants use second-type devices to detect photons. In this case, the secret key can be successfully distributed from Alice to the other three ones. Moreover, the present four-party QKD scheme can be generalized to a 2n-party QKD scheme by using n-photon Greenberg–Horne–Zeilinger.

Ting Wang, Dongning Zhao, Zhiwei Sun +1 more

A quantum key distribution protocol with traditional Bob has been proposed recently by Boyer et al. using single-particle state.In this paper, a semi-quantum key distribution protocol is described, in which Einstein-Podolsky-Rosen (EPR) pairs of particles are utilized to generate a secret key in remote places.This extends the quantum key distribution protocol with traditional Bob where the single-qubit channel is replaced by the entangled EPR-pair channel.And quantum Alice is able to do any quantum operations, preparing quantum states and performing quantum measurement, but traditional Bob is not able to prepare and measure a particle in the computational basis, reflect the particles.Furthermore, entanglement states are used in our protocol.The analysis shows that our protocol is secure, which can avoid the beam splitter attack automatically, and the proposed protocol is more efficient than Boyer's scheme.