Comment on 'Multiparty Quantum Key Agreement with GHZ State'

Abstract

Recently, Chen et al. (DOI 10.1109/SMC.2015. 281) proposed a multiparty quantum key agreement protocol based on Greenberger—Horne—Zeilinger (GHZ) state. They claimed that their protocol can achieve both the security property and the fairness property. However, this study points out that Chen et al.'s protocol cannot achieve the fairness property by an Internal Attack. That is, one of the involved participant (Alice) can determine the final key alone without being detected by other participants.