A Privacy-Preserving Comparison Protocol
Kartick Sutradhar, Hari Om · IEEE Transactions on Computers · 2022
Themultiparty comparisonallows to compare two integers$x$and$y$blindly, where a set of players hold the shares of the elements$x and y, x, y \in \mathbb {F}_{p}$, a prime field. The existingmultiparty comparisonprotocols execute in constant rounds, but the number of multiplications depends on the size of the prime$p$, i.e., the communication complexity will be high for large prime$p$. In this paper, we present amultiparty comparisonprotocol with constant rounds in which the number of multiplications depends on the number of players rather than the prime$p$itself. Thismultiparty comparisonprotocol is further extended to design amultiparty equality-testprotocol. An equality-test protocol computes the equality of shares in constant rounds and its number of multiplications depends on the number of players. Our proposed protocolsmultiparty comparisonand equality-test are unconditionally secure against the active and passive attacks and have$O(n)$communication complexity, where$n$is the number of players. We also present an efficient technique forfault detectionthat can verify the correctness of various protocols.