# Prysmatic Labs Main Sharding Reference

Table of Contents
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- Sharding Introduction
  - Basic Sharding Idea and Design
- Roadmap Phases
  - The Ruby Release: Local Alphanet
  - The Sapphire Release: Ropsten Testnet
  - The Diamond Release: Ethereum Mainnet
- Go-Ethereum Sharding Alpha Implementation
  - System Architecture
  - System Start & User Entrypoint
  - The Validator Manager Contract
    - Necessary Functionality
      - Depositing ETH and Becoming a Validator
      - Determining an Eligible Proposer for a Period on a Shard
      - Withdrawing From the Validator Set
      - Processing and Verifying a Collation Header
    - Validator Sampling
    - Collation Header Approval
    - Event Logs
  - The Validator Client
    - Local Shard Storage
  - The Proposer Client
    - Collation Headers and State Execution
  - Peer Discovery and Shard Wire Protocol
  - Protocol Modifications
    - Protocol Primitives: Collations, Blocks, Transactions, Accounts
    - The EVM: What You Need to Know
  - Sharding In-Practice
    - Fork Choice Rule
    - Use-Case Stores: Proposers
    - Use-Case Stories: Validators
    - Use-Case Stories: Supernodes
  - Current Status
- Security Considerations
  - Not Included in Ruby Release
  - Bribing, Coordinated Attack Models
  - Enforced Windback
    - Explicity Finality for Stateless Clients
  - The Data Availability Problem
    - Introduction & Background
    - On Uniquely Attributable Faults
    - Erasure Codes
- Beyond Phase 1
  - Cross-Shard Communication
    - Receipts Method
    - Merge Blocks
    - Synchronous State Execution
  - Transparent Sharding
  - Tightly-Coupled Sharding (Fork-Free Sharding)
- Active Questions & Research
  - Separation of Proposals & Consensus
  - Selecting Eligible Validators Off-Chain
- Community Updates & Contributions
- References