Multi-user private comparison protocol using GHZ class states

Yao Jen Chang, Chia Wei Tsai, Tzonelih Hwang

Research output: Contribution to journalArticlepeer-review

83 Citations (Scopus)


This paper proposes a pioneering quantum private comparison (QPC) protocol for n users. State-of-the-art QPC protocols have been designed for two users who wish to compare their private information. However, if n users want to perform the equality comparison, these two-user QPC protocols have to be executed repeatedly at least n - 1 times. The proposed protocol allows n users' private information to be compared within one protocol execution. The proposed QPC protocol takes the Greenberger-Horne-Zeilinger (GHZ) class as a quantum resource and uses a special property in the GHZ-class state to perform the equality comparison. Moreover, due to the one-step quantum transmission, the protocol is free from Trojan horse attacks and it is also shown to be secure against other well-known attacks.

Original languageEnglish
Pages (from-to)1077-1088
Number of pages12
JournalQuantum Information Processing
Issue number2
Publication statusPublished - 2013 Feb

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Statistical and Nonlinear Physics
  • Theoretical Computer Science
  • Signal Processing
  • Modelling and Simulation
  • Electrical and Electronic Engineering


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