Secure matchmaking protocol

Abstract

Matchmaking protocol is a procedure to find matched pairs in registered groups of participants depending on their choices, while preserving their privacy. In this study we define the concept of matchmaking and construct a simple and efficient matchmaking protocol under the simple rule that two members become a matched pair only when they have chosen each other. In matchmaking protocol, participant’s privacy is of prime concern, specially losers' choices should not be opened. Our basic approach to achieve privacy is finding collisions among multiple secure commitments without decryption. For this purpose we build a protocol to find collisions in ElGamal ciphertexts without decryption using Michels and Stadler’s protocol [MS97] of proving the equality or inequality of two discrete logarithms. Correctness is guaranteed because all procedures are universally verifiable.