A Game theoretic approach for validator selection in proof of stake blockchains

Abstract

In our study, we propose a novel validator selection mechanism for Proof-of-Stake blockchains that utilizes game theory through a Vickrey auction mechanism to encourage honest staking. The main element of our contribution is to include an auction mechanism that prevents domination by high-stake validators and a weighted random selection process to ensure fairness, and we aim to address a gap in selection methods that advantage nodes with more resources. The rationale for our approach is based on other game-theoretic approaches used in production-grade blockchains like Algorand, Avalanche, and Prism. We introduce a payment mechanism similar to a classic “stag hunt” scenario for mutual benefit through honest bidding. We propose a consensus mechanism that combines a weighted lottery pool and a second-price auction system for candidate selection and cost calculation. Our model incentivizes nodes to bid truthfully, reflecting their true value estimation of validating a block. We set up a PoS blockchain, the initialization of nodes and violators, and proceeded to simulate the addition of new blocks. We record the conditions of the bids and rewards to demonstrate that our mechanism promotes a fairer stake distribution while minimizing disparity among validators. Although a perfectly equitable system is challenging to design, our method offers a significant step towards a more equitable, secure, and efficient blockchain system.