The finality gadget

Putting eth2.0 to work…

Successive spans of proof-of-work blocks finalized by the proof-of-stake consensus


How it works

A validator becomes active on Ethereum 2.0 after inclusion of a valid deposit from the 1.0 chain and a queuing period.
The beacon chain maintains the state of the deposit contract on the 1.0 chain to verify deposit proofs. The block hash for the block resulting in the recorded state is also stored.
The process of voting for a particular proof-of-work block. Each block has a unique hash; the color is a shorthand for the hash. The small squares represent votes for a particular 1.0 block made by a validator. The voting process starts over in each period of time (described below), demarked by the ticks on the solid black line. Only the first two periods have finalized on the beacon chain, so only part of the 1.0 chain has been finalized in this diagram. Credits to Alexey for the coloring scheme idea :)
This diagram shows some parameters relating to timing in Ethereum 2.0. Current numbers are: 6 seconds for a slot, and 1024 slots per voting period (~1.4 hrs).
Diagram showing the follow distance. There are three voting periods, each a distinct chunk of time. We can see the candidate blocks (shaded) for each period, based on their distance from the tip of the chain. This number of blocks is the ETH1_FOLLOW_DISTANCE. Here it is two blocks; it is currently set to 1024 blocks in the 2.0 specification.

Why do we want it?

How do we get it?

Risks to the finality gadget

Open questions




ethereum r&d

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