1c8d57eeb7
This PR, a continuation of 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 that particular state without executing the transitions, and without checking them one by one in backwards order using a parent chain. This is interesting for archival purposes as well as when implementing sync protocols that can verify chunks of blocks quickly, meaning they can be downloaded in any order. 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 this PR, `historical_roots` is frozen at its current value and `historical_batches` are computed from the merge epoch onwards. After this PR, `block_batch_root` in the state can be used to verify an era of blocks against the state with a simple root check. The `historical_roots` values on the other hand can be used to verify that a constant distributed with clients is valid for a particular state, and therefore extends the block validation all the way back to genesis without backfilling `block_batch_root` and without introducing any new security assumptions in the client. As far as naming goes, it's convenient to talk about an "era" being 8192 slots ~= 1.14 days. The 8192 number comes from the SLOTS_PER_HISTORICAL_ROOT constant. With multiple easily verifable blocks in a file, it becomes trivial to offload block history to out-of-protocol transfer methods (bittorrent / ftp / whatever) - including execution payloads, paving the way for a future in which clients purge block history in p2p. This PR can be applied along with the merge which simplifies payload distribution from the get-go. Both execution and consensus clients benefit because from the merge onwards, they both need to be able to supply ranges of blocks in the sync protocol from what effectively is "cold storage". Another possibility is to include it in a future cleanup PR - this complicates the "cold storage" mode above by not covering exection payloads from start.
Ethereum Proof-of-Stake Consensus Specifications
To learn more about proof-of-stake and sharding, see the PoS FAQ, sharding FAQ and the research compendium.
This repository hosts the current Ethereum proof-of-stake 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 Ethereum proof-of-stake clients can be found in specs. These are divided into features. Features are researched and developed in parallel, and then consolidated into sequential upgrades when ready.
Stable Specifications
| Seq. | Code Name | Fork Epoch | Specs |
|---|---|---|---|
| 0 | Phase0 | 0 |
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| 1 | Altair | 74240 |
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| 2 | Bellatrix ("The Merge") |
144896 |
In-development Specifications
| Code Name or Topic | Specs | Notes |
|---|---|---|
| Capella (tentative) |
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| EIP4844 (tentative) | ||
| Sharding (outdated) |
|
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| Custody Game (outdated) |
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Dependent on sharding |
| Data Availability Sampling (outdated) |
|
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 the Ethereum proof-of-stake consensus specifications:
- 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:
Consensus spec tests
Conformance tests built from the executable python spec are available in the Ethereum Proof-of-Stake Consensus Spec Tests repo. Compressed tarballs are available in releases.