658e92af96
This PR simplifies and replaces `historical_roots` with `historical_block_roots`. By keeping an accumulator of historical block roots in the state, it becomes possible to validate the entire block history that led up to a particular state without executing the transitions. This is interesting for archival purposes as well as when implementing sync protocols that can then proceed to verify chunks of blocks quickly - it's also useful as it provides a canonical hash by which such chunks of blocks can be named, with a direct reference in the state. In order not to grow the state size further, the `historical_roots` field is removed - the blocks already contain state roots, so the value of repeating the state root in the historical accumulator is limited to empty slots, and even then, the historical block root accumulator differentiates states that differ by empty slots. This is a sketch of the full PR - there are a few key decisions to make: * should the historical block roots be backfilled with phase0 data on the transition? This simplifies future logic but could be omitted for simplicity. It's easy to precalculate what the values should be, so it's not a computational issue. * should historical roots remain? As far as naming goes, it's convenient to talk about an "era" being 8192 epoch = 256k slots ~= 36.4 days.
Ethereum 2.0 Specifications
To learn more about sharding and Ethereum 2.0 (Serenity), see the sharding FAQ and the research compendium.
This repository hosts the current Eth2 specifications. Discussions about design rationale and proposed changes can be brought up and discussed as issues. Solidified, agreed-upon changes to the spec can be made through pull requests.
Specs
Core specifications for Eth2 clients be found in specs. These are divided into features. Features are researched and developed in parallel, and then consolidated into sequential upgrades when ready.
The current features are:
Phase 0
- The Beacon Chain
- Beacon Chain Fork Choice
- Deposit Contract
- Honest Validator
- P2P Networking
- Weak Subjectivity
Altair
- Beacon chain changes
- Altair fork
- Light client sync protocol
- Honest Validator guide changes
- P2P Networking
Merge
The merge is still actively in R&D. The specifications outline a general direction for engineering work, while the details are in review and may change.
- Background material:
- An ethresear.ch post describing the basic mechanism
- ethereum.org high-level description of the merge here
- Specifications:
Sharding
Sharding follows the merge, and is divided into three parts:
- Sharding base functionality - In early engineering phase
- Custody Game - Ready, dependent on sharding
- Data Availability Sampling - In active R&D
- Technical details here.
- Core types and functions
- P2P Networking
- Fork Choice
- Sampling process
Accompanying documents can be found in specs and include:
Additional specifications for client implementers
Additional specifications and standards outside of requisite client functionality can be found in the following repos:
Design goals
The following are the broad design goals for Ethereum 2.0:
- to minimize complexity, even at the cost of some losses in efficiency
- to remain live through major network partitions and when very large portions of nodes go offline
- to select all components such that they are either quantum secure or can be easily swapped out for quantum secure counterparts when available
- to utilize crypto and design techniques that allow for a large participation of validators in total and per unit time
- to allow for a typical consumer laptop with
O(C)resources to process/validateO(1)shards (including any system level validation such as the beacon chain)
Useful external resources
For spec contributors
Documentation on the different components used during spec writing can be found here: