Reexamination of arbitrated quantum signature: the impossible and the possible

Abstract

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.