Co-Utility: Self-Enforcing Protocols without Coordination Mechanisms

TL;DR

This paper introduces co-utile protocols, a new type of self-enforcing protocol that operates without coordination mechanisms, enhancing efficiency and fairness in decentralized rational-agent systems, with applications in privacy preservation.

Contribution

It proposes co-utile protocols as a novel solution that overcomes limitations of traditional self-enforcing protocols requiring coordination mechanisms.

Findings

Co-utile protocols eliminate the need for coordination mechanisms.

They improve efficiency and fairness in decentralized systems.

Application demonstrated in preserving user privacy in IT systems.

Abstract

Performing some task among a set of agents requires the use of some protocol that regulates the interactions between them. If those agents are rational, they may try to subvert the protocol for their own benefit, in an attempt to reach an outcome that provides greater utility. We revisit the traditional notion of self-enforcing protocols implemented using existing game-theoretic solution concepts, we describe its shortcomings in real-world applications, and we propose a new notion of self-enforcing protocols, namely co-utile protocols. The latter represent a solution concept that can be implemented without a coordination mechanism in situations when traditional self-enforcing protocols need a coordination mechanism. Co-utile protocols are preferable in decentralized systems of rational agents because of their efficiency and fairness. We illustrate the application of co-utile protocols to information technology, specifically to preserving the privacy of query profiles of database/search engine users.