English

Bribers, Bribers on The Chain, Is Resisting All in Vain? Trustless Consensus Manipulation Through Bribing Contracts

Cryptography and Security 2026-01-14 v2

Abstract

The long-term success of cryptocurrencies largely depends on the incentive compatibility provided to the validators. Bribery attacks, facilitated trustlessly via smart contracts, threaten this foundation. This work introduces, implements, and evaluates three novel and efficient bribery contracts targeting Ethereum validators. The first bribery contract enables a briber to fork the blockchain by buying votes on their proposed blocks. The second contract incentivizes validators to voluntarily exit the consensus protocol, thus increasing the adversary's relative staking power. The third contract builds a trustless bribery market that enables the briber to auction off their manipulative power over the RANDAO, Ethereum's distributed randomness beacon. Finally, we provide an initial game-theoretical analysis of one of the described bribery markets.

Keywords

Cite

@article{arxiv.2509.17185,
  title  = {Bribers, Bribers on The Chain, Is Resisting All in Vain? Trustless Consensus Manipulation Through Bribing Contracts},
  author = {Bence Soóki-Tóth and István András Seres and Kamilla Kara and Ábel Nagy and Balázs Pejó and Gergely Biczók},
  journal= {arXiv preprint arXiv:2509.17185},
  year   = {2026}
}

Comments

To appear at Financial Cryptography and Data Security 2026