How to Rationally Select Your Delegatee in PoS

TL;DR

This paper investigates how individual users select delegatees in proof-of-stake protocols, proposing a Bayesian trust model and game-theoretical analysis to understand delegation behaviors and their impact on token distribution.

Contribution

It introduces a Bayesian trust model combined with game theory to analyze user delegation choices in PoS, addressing a previously overlooked aspect of committee formation.

Findings

Users weigh delegation cost, delegatee reputation, and others' behaviors in their choices.

Delegation strategies tend to lead to token concentration among few delegatees.

The model predicts a Nash equilibrium in user delegation behaviors.

Abstract

This paper centers around a simple yet crucial question for everyday users: How should one choose their delegated validators within proof-of-stake (PoS) protocols, particularly in the context of Ethereum 2.0? This has been a long-overlooked gap, as existing studies have primarily focused on inter-committee (validator set) behaviors and activities, while neglecting the dynamic formation of committees, especially for individual stakeholders seeking reliable validators. Our study bridges this gap by diving into the delegation process (normal users delegate their small-value tokens to delegatees who later act as validators) before entering an actual consensus phase. We propose a Bayesian model to quantify normal users' trust in delegatees, which we further incorporate into a game-theoretical model to simulate users' reactions against a set of critical factors identified through extensive research (including 10+ staking service provider as well as 30+ PoS blockchains). Our results reveal that users tend to choose their delegatees and utilize their tokens by carefully weighing the delegation cost, the behaviors of other users, and the reputation of delegatees, ultimately reaching a Nash equilibrium. Unfortunately, the collective trend significantly increases the likelihood of token concentration on a small number of delegatees.