A Quantum Detectable Byzantine Agreement Protocol Using Only EPR Pairs

Abstract

In this paper, we introduce a new quantum protocol for Detectable Byzantine Agreement. What distinguishes the proposed protocol among similar quantum protocols, is the fact that it uses only EPR pairs, and, in particular, |Ψ+⟩ pairs. There are many sophisticated quantum protocols that guarantee Detectable Byzantine Agreement, but they do not easily lend themselves to practical implementations, due to present-day technological limitations. For a large number n of players, |GHZ⟩n-tuples, or other more exotic entangled states, are not easy to produce, a fact which might complicate the scalability of such protocols. In contrast, Bell states are, undoubtedly, the easiest to generate among maximally entangled states. This will, hopefully, facilitate the scalability of the proposed protocol, as only EPR pairs are required, irrespective of the number n of players. Finally, we mention that, even for arbitrary many players n, our protocol always completes in a constant number of rounds, namely 4.