Rational Censorship Attack: Breaking Blockchain with a Blackboard

Fuente: arXiv
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Auteurs principaux: Yeo, Michelle, Zhang, Haoqian
Format: Preprint
Publié: 2025
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author Yeo, Michelle
Zhang, Haoqian
author_facet Yeo, Michelle
Zhang, Haoqian
contents Censorship resilience is a fundamental assumption underlying the security of blockchain protocols. Additionally, the analysis of blockchain security from an economic and game theoretic perspective has been growing in popularity in recent years. In this work, we present a surprising rational censorship attack on blockchain censorship resilience when we adopt the analysis of blockchain security from a game theoretic lens and assume all users are rational. In our attack, a colluding group with sufficient voting power censors the remainder nodes such that the group alone can gain all the rewards from maintaining the blockchain. We show that if nodes are rational, coordinating this attack just requires a public read and write blackboard and we formally model the attack using a game theoretic framework. Furthermore, we note that to ensure the success of the attack, nodes need to know the total true voting power held by the colluding group. We prove that the strategy to join the rational censorship attack and also for nodes to honestly declare their power is a subgame perfect equilibrium in the corresponding extensive form game induced by our attack. Finally, we discuss the implications of the attack on blockchain users and protocol designers as well as some potential countermeasures.
format Preprint
id arxiv_https___arxiv_org_abs_2507_01453
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Rational Censorship Attack: Breaking Blockchain with a Blackboard
Yeo, Michelle
Zhang, Haoqian
Computer Science and Game Theory
Cryptography and Security
Distributed, Parallel, and Cluster Computing
Censorship resilience is a fundamental assumption underlying the security of blockchain protocols. Additionally, the analysis of blockchain security from an economic and game theoretic perspective has been growing in popularity in recent years. In this work, we present a surprising rational censorship attack on blockchain censorship resilience when we adopt the analysis of blockchain security from a game theoretic lens and assume all users are rational. In our attack, a colluding group with sufficient voting power censors the remainder nodes such that the group alone can gain all the rewards from maintaining the blockchain. We show that if nodes are rational, coordinating this attack just requires a public read and write blackboard and we formally model the attack using a game theoretic framework. Furthermore, we note that to ensure the success of the attack, nodes need to know the total true voting power held by the colluding group. We prove that the strategy to join the rational censorship attack and also for nodes to honestly declare their power is a subgame perfect equilibrium in the corresponding extensive form game induced by our attack. Finally, we discuss the implications of the attack on blockchain users and protocol designers as well as some potential countermeasures.
title Rational Censorship Attack: Breaking Blockchain with a Blackboard
topic Computer Science and Game Theory
Cryptography and Security
Distributed, Parallel, and Cluster Computing
url https://arxiv.org/abs/2507.01453