A cost-effective pay-per-multiplication comparison method for millionaires

Abstract

Based on the quadratic residuosity assumption we present a non-interactive crypto-computing protocol for the greater-than func-tion, i. e., a non-interactive procedure between two parties such that only the relation of the parties' inputs is revealed. In comparison to previous solutions our protocol reduces the number of modular multiplications sig-nificantly. We also discuss applications to conditional oblivious transfer, private bidding and the millionaires' problem.