Cryptanalysis of multiparty quantum digital signatures

Abstract

Multiparty quantum digital signatures play an important role in quantum networks which sign and distribute message among users with information-theoretic security. In this work, we give a cryptanalysis of a multiparty quantum digital signature scheme and then propose a new attacks strategy, whereby dishonest participants can frame an honest participant if they collude with each other. To prevent the framing attack, we study the relations between the signing key and each verification key, as well as the relations among different verification keys in this scheme, and then give the security requirements on the relations among different keys, which is also very useful for the next development of multiparty quantum digital signature schemes. Finally, we present a possible way to solve the security problem.