# Ethereum 2.0 Specifications [![Join the chat at https://discord.gg/hpFs23p](https://img.shields.io/badge/chat-on%20discord-blue.svg)](https://discord.gg/hpFs23p) [![Join the chat at https://gitter.im/ethereum/sharding](https://badges.gitter.im/ethereum/sharding.svg)](https://gitter.im/ethereum/sharding?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge) To learn more about sharding and Ethereum 2.0 (Serenity), see the [sharding FAQ](https://github.com/ethereum/wiki/wiki/Sharding-FAQ) and the [research compendium](https://notes.ethereum.org/s/H1PGqDhpm). 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/](specs/). These are divided into phases. Each subsequent phase depends upon the prior. The current phases specified are: ### Phase 0 * [The Beacon Chain](specs/phase0/beacon-chain.md) * [Fork Choice](specs/phase0/fork-choice.md) * [Deposit Contract](specs/phase0/deposit-contract.md) * [Honest Validator](specs/phase0/validator.md) * [P2P Networking](specs/phase0/p2p-interface.md) ### Phase 1 * [From Phase 0 to Phase 1](specs/phase1/phase1-fork.md) * [The Beacon Chain for Shards](specs/phase1/beacon-chain.md) * [Custody Game](specs/phase1/custody-game.md) * [Shard Transition and Fraud Proofs](specs/phase1/fraud-proofs.md) * [Light client syncing protocol](specs/phase1/light-client-sync.md) ### Phase 2 Phase 2 is still actively in R&D and does not yet have any formal specifications. See the [Eth2 Phase 2 Wiki](https://hackmd.io/UzysWse1Th240HELswKqVA?view) for current progress, discussions, and definitions regarding this work. ### Accompanying documents can be found in [specs](specs) and include: * [SimpleSerialize (SSZ) spec](ssz/simple-serialize.md) * [Merkle proof formats](ssz/merkle-proofs.md) * [General test format](tests/formats/README.md) ## Additional specifications for client implementers Additional specifications and standards outside of requisite client functionality can be found in the following repos: * [Eth2 APIs](https://github.com/ethereum/eth2.0-apis) * [Eth2 Metrics](https://github.com/ethereum/eth2.0-metrics/) * [Interop Standards in Eth2 PM](https://github.com/ethereum/eth2.0-pm/tree/master/interop) ## 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/validate `O(1)` shards (including any system level validation such as the beacon chain) ## Useful external resources * [Design Rationale](https://notes.ethereum.org/s/rkhCgQteN#) * [Phase 0 Onboarding Document](https://notes.ethereum.org/s/Bkn3zpwxB) * [Combining GHOST and Casper paper](https://arxiv.org/abs/2003.03052) ## For spec contributors Documentation on the different components used during spec writing can be found here: * [YAML Test Generators](tests/generators/README.md) * [Executable Python Spec, with Py-tests](tests/core/pyspec/README.md)