Computational cryptography › Live on mainnet today
Honest stake
In plain words
Not math: Ethereum assumes most staked ETH behaves honestly.
Why it matters: Cryptography stops forgery. Only incentives and slashing stop dishonest validators.
The details
On the map: conflicting finality needs ≥ 1/3 of stake slashed, finalizing needs > 2/3 online (not cryptographic)
Not a cryptographic assumption: Ethereum's consensus (Gasper)[1] assumes most stake behaves honestly.
- Finalizing a checkpoint needs more than 2/3 of stake voting for it.
- Finalizing two conflicting checkpoints would need at least 1/3 of stake to sign contradictory votes, which is provable and gets slashed[2].
- If more than 1/3 goes offline, finality stops and the inactivity leak gradually removes their stake until it resumes[3].
Cryptography makes votes unforgeable. It can't make validators honest.
Rests on
If any of these breaks, this breaks too.
If it falls
If this breaks, these break with it.
Everything that falls with it (4 boxes)
References
- Vitalik Buterin, Diego Hernandez, Thor Kamphefner et al. Combining GHOST and Casper. arXiv:2003.03052, 2020. arxiv.org/abs/2003.03052
- Vitalik Buterin and Virgil Griffith. Casper the Friendly Finality Gadget. arXiv:1710.09437, 2017. arxiv.org/abs/1710.09437
- Ethereum consensus-specs authors. Phase 0: The Beacon Chain (consensus-specs). ethereum/consensus-specs, 2020. github.com/ethereum/consensus-specs/blob/master/specs/phase0/beacon-chain.md