Ting-Ting Song

Security analysis of quantum multi-signature protocol based on teleportation

The security of the recent quantum multi-signature protocol based on teleportation is analyzed. We show that there are some security vulnerabilities in the protocol. The detailed attack strategies are described from the aspect of participant attack. We also point out that the protocol is not secure against external attack. Finally, we give some possible countermeasures to improve the protocol.

Reexamination of arbitrated quantum signature: the impossible and the possible

As a new model for signing both quantum and classical messages, the arbitrated quantum signature (AQS) protocols have recently attracted a lot of attentions. In this paper, we analyze their security from an important security aspect—the receiver’s forgery of the signature, and provide a detailed proof of the fact that the attempt to design an improved optimal encryption used in AQS cannot prevent the receiver’s forgery attack unless some assistant security strategies are introduced. In order to show that, we firstly summarize an explicit formalization of the general AQS model and propose the necessary and sufficient conditions against the receiver’s forgery attack. Then a contradiction of them has been pointed out. In order to complete our security analysis, we verify that the AQS protocols for signing classic messages are still susceptible to the receiver’s forgery. Finally, some assistant security strategies are provided to recover the security.

Finite-key security analyses on passive decoy-state QKD protocols with different unstable sources

In quantum communication, passive decoy-state QKD protocols can eliminate many side channels, but the protocols without any finite-key analyses are not suitable for in practice. The finite-key securities of passive decoy-state (PDS) QKD protocols with two different unstable sources, type-II parametric down-convention (PDC) and phase randomized weak coherent pulses (WCPs), are analyzed in our paper. According to the PDS QKD protocols, we establish an optimizing programming respectively and obtain the lower bounds of finite-key rates. Under some reasonable values of quantum setup parameters, the lower bounds of finite-key rates are simulated. The simulation results show that at different transmission distances, the affections of different fluctuations on key rates are different. Moreover, the PDS QKD protocol with an unstable PDC source can resist more intensity fluctuations and more statistical fluctuation.

Anonymous quantum communications using the quantum one-time pad

We present the first quantum secure communication protocol for an anonymous receiver without the assistance of anonymous entanglement. In previous works, if a public sender wants to send quantum messages to a chosen receiver while protecting the identity of the receiver from others, all participants should cooperate first to construct the entanglement between the sender and the anonymous receiver. This is the most important process in anonymous quantum communications. With anonymous entanglement, the sender can communicate quantum messages to the anonymous receiver by applying teleportation protocols. In contrast, our protocol is novel and achieves communication of quantum messages directly from the public sender to the anonymous receiver based on the quantum one-time pad and current achievements. Notably, the anonymity of the receiver, as well as the privacy of the quantum messages, is perfectly protected with the exception of an exponentially small probability in our protocol.

The general theory of three-party quantum secret sharing protocols over phase-damping channels

The general theory of three-party QSS protocols with the noisy quantum channels is discussed. When the particles are transmitted through the noisy quantum channels, the initial pure three-qubit tripartite entangled states would be changed into mixed states. We analyze the security of QSS protocols with the different kinds of three-qubit tripartite entangled states under phase-damping channels and figure out, for different kinds of initial states, the successful probabilities that Alice’s secret can be recovered by legal agents are different. Comparing with one recent QSS protocol based on GHZ states, our scheme is secure, and has a little smaller key rate than that of the recent protocol.

DISCUSSION ON QUANTUM PROXY GROUP SIGNATURE SCHEME WITH χ-TYPE ENTANGLED STATE

Recently, Yin et al. (Int. J. Quantum Inform. 10 (2012) 1250041) proposed a quantum proxy group signature scheme with χ-type entangled states. The scheme combines the properties of group signature and proxy signature. The study points out that the semi-honest Trent can give the forged signature under the assumption of this scheme. And, we find that even if the three parties honestly perform the scheme, the signature still cannot be realized with high efficiency.