‘Ethereum 2 is coming’ has been the tagline of the Ethereum community for the past several years. However, the new phase, Serenity, is set to come to fruition soon, with the team outlining 2020 as the year it would start rolling out. Serenity would be launching in three phases – phase zero, phase 1, and phase 2. Phase zero, the first phase to launch, would be introducing the beacon chain, whereas phase one and phase two would introduce shard chains and execution layer and would be probably making a debut simultaneously.
In an interview for EthHub, Paul Hauner, a developer at Sigma Prime, spoke about the Beacon chain‘s role. Hauner remarked that the first phase of Serenity “primarily exists like just for the sake of existing,” stating that it would not “really support anything else.” Nevertheless, he stated that in the bigger picture, the beacon chain would act like a “central coordination chain,” the homestead of validators. He said,
“it’s where all the validators live, it’s where we manage the validators and that balances, it’s where we kind of make assessments about what the majority of the validators are voting on and we ban them for doing bad things […] it’s like this kind of validated management chain that also serves as a bit of an anchor to the shard chains […]”
The developer went on to state that the proof-of-stake blockchain would host slots for “other parallel execution systems,” remarking that it would be the main coordinating layout aka “the Loadstar” of the system.
Subsequently, Hauner briefly expanded on finality, stating, “idea with finality is that there’s some block in the chain and it’s impossible for that block to be reverted unless two-thirds of the validators make some slashable vote on that block.” He further said that in the case of Eth 2, there is an “honest majority assumption,” where it is assumed that the majority of validators are honest. He added,
“It’s very difficult to do away with this assumption because if you can’t listen to the majority then there’s obviously no actual source of universal truth; so you just have to kind of listen to the majority.”
Hauner concluded by stating,
“Because we listen to the majority if we can observe that they’ve all voted on some block and we can make a statement saying that there’s no way for the validators to vote in a way that excludes this block that isn’t an equivocation or a lie or a double vote from them. so once we can make this statement about a block then we can say okay so this block is final”