Hidden Elo: Private Matchmaking through Encrypted Rating Systems

TL;DR

H-Elo is a novel FHE-based private rating system enabling secure matchmaking that maintains accuracy while protecting sensitive data, applicable across various domains.

Contribution

This work introduces H-Elo, one of the first private rating systems using FHE for secure matchmaking, with security analysis and benchmarking in a chess scenario.

Findings

H-Elo achieves similar accuracy to plaintext rating systems.

H-Elo maintains privacy and security of rating values.

Benchmark results demonstrate practical performance in a chess scenario.

Abstract

Matchmaking has become a prevalent part in contemporary applications, being used in dating apps, social media, online games, contact tracing and in various other use-cases. However, most implementations of matchmaking require the collection of sensitive/personal data for proper functionality. As such, with this work we aim to reduce the privacy leakage inherent in matchmaking applications. We propose H-Elo, a Fully Homomorphic Encryption (FHE)-based, private rating system, which allows for secure matchmaking through the use of traditional rating systems. In this work, we provide the construction of H-Elo, analyse the security of it against a capable adversary as well as benchmark our construction in a chess-based rating update scenario. Through our experiments we show that H-Elo can achieve similar accuracy to a plaintext implementation, while keeping rating values private and secure. Additionally, we compare our work to other private matchmaking solutions as well as cover some future directions in the field of private matchmaking. To the best of our knowledge we provide one of the first private and secure rating system-based matchmaking protocols.