# "Zero Cost'' Majority Attacks on Permissionless Blockchains

arXiv: https://arxiv.org/abs/2308.06568 · HTML: https://mlsanity.com/paper/2308.06568/

## Key facts

- Cited by 3 papers in the map (data through 14 Oct 2026).
- First posted on arXiv 12 Aug 2023.

## Built on by (most cited first, 3 of 3)

- [Game of Coding: Sybil Resistant Decentralized Machine Learning with Minimal Trust Assumption](https://mlsanity.com/paper/2410.05540/) (2024)
- [Game of Coding With an Unknown Adversary](https://mlsanity.com/paper/2502.07109/) (2025)
- [Learning from Acceptance: Cumulative Regret in the Game of Coding](https://mlsanity.com/paper/2605.09754/) (2026)

## Abstract (arXiv)

The core premise of permissionless blockchains is their reliable and secure operation without the need to trust any individual agent. At the heart of blockchain consensus mechanisms is an explicit cost (whether work or stake) for participation in the network and the opportunity to add blocks to the blockchain. A key rationale for that cost is to make attacks on the network, which could be theoretically carried out if a majority of nodes were controlled by a single entity, too expensive to be worthwhile. We demonstrate that a majority attacker can successfully attack with a em negative cost, which shows that the protocol mechanisms are insufficient to create a secure network, and emphasizes the importance of socially driven mechanisms external to the protocol. At the same time, negative cost enables a new type of majority attack that is more likely to elude external scrutiny.