  Quantum digital signatures (QDSs) promise information-theoretic security
against repudiation and forgery of messages. Compared with currently existing
three-party QDS protocols, multiparty protocols have unique advantages in the
practical case of more than two receivers when sending a mass message. However,
complex security analysis, numerous quantum channels and low data utilization
efficiency make it intractable to expand three-party to multiparty scenario.
Here, based on six-state non-orthogonal encoding protocol, we propose an
effective multiparty QDS framework to overcome these difficulties. The number
of quantum channels in our protocol only linearly depends on the number of
users. The post-matching method is introduced to enhance data utilization
efficiency and make it linearly scale with the probability of detection events
even for five-party scenario. Our work compensates for the absence of practical
multiparty protocols, which paves the way for future QDS networks.
