Improvement of security of three-party quantum secure direct communication based on GHZ states

摘要

A protcol for three-party quantum secure direct communication based on Greenberger-Horne-Zeilinger (GHZ) states was recently proposed by Jin et al. [Phys. Lett. A 354(2006)67] By analysing the protcol we find some security loopholes, e.g. one bit of secret messages of a party (Alice in the orginal paper) can always be leaked straight to the public without any eavesdropping. These problems suggested previously are discussed amd possible solutions are present to improve the security of the orginal protocol.