Guangqiang He

CONTINUOUS VARIABLE QUANTUM SIGNATURE ALGORITHM

A true quantum signature algorithm based on continuous-variable entanglement state is proposed. In the suggested algorithm, a key-pair, i.e. private signature key and public verification key, is generated based on a one-way function. By employing the signature key, a message state is encoded into a 2k-particle entangled state and a two-particle entangled state is prepared. The resulting states are exploited as a signature of the message state. The signature can be decoded under the verification key when it needs to be verified. Subsequently, a decoded message state and a two-particle entangled state are obtained. To compare the decoded states and the original states, a quantum circuit for comparing these states is exploited. Making use of measurement results of the quantum circuit one can judge the authenticity of the received signature. According to the security requirement of the signature scheme, the suggested algorithm has been proven to be theoretically secure by using the Shannon information theory.

Continuous-variable measurement-device-independent multipartite quantum communication

A continuous-variable measurement-device-independent multiparty quantum communication protocol is investigated in this paper. Utilizing the distributed continuous-variable Greenberger-Horne-Zeilinger state, this protocol can implement both quantum cryptographic conference and quantum secret sharing. We analyze the security of the protocol against both the entangling cloner attack and the coherent attack. The entangling cloner attack is a practical individual attack, and the coherent attack is the optimal attack Eve can implement. Simulation results show that the coherent attack can greatly reduce the secret key rate. Different kinds of entangled attacks are compared and we finally discuss the optimal coherent attacks.

Quantum secret sharing with continuous variable graph state

In this paper, we study several physically feasible quantum secret sharing (QSS) schemes using continuous variable graph state (CVGS). Their implementation protocols are given, and the estimation error formulae are derived. Then, we present a variety of results on the theory of QSS with CVGS. Any

Study on the security of discrete-variable quantum key distribution over non-Markovian channels

(k,n)

Quantum network dense coding via continuous-variable graph states

(k,n) threshold protocol of the three specific schemes satisfying

Five-partite entanglement generation in a high- Q microresonator

\frac{n}{2}<k\le n