Permissioned L1s Review

What are Permissioned L1s?

Permissioned L1s are Layer 1 blockchains where validator participation is controlled by a central authority rather than being open to anyone. Unlike permissionless networks where anyone can become a validator by staking tokens, permissioned L1s use Proof of Authority (PoA) as their sybil protection mechanism.

Proof of Authority (PoA)

Proof of Authority is a sybil protection mechanism that centralizes control over who can validate the network to one account (EoA or multi-sig). Instead of requiring validators to stake tokens (like Proof of Stake), PoA leverages real-world identity and reputation.

Key Characteristics:

• Known Entities: Validators are operated by trusted organizations
• Reputation-Based: Validators risk damaging real-world reputation if they misbehave
• Weight-Based Influence: Validators can have different voting weights
• No Economic Incentives: Validators don't receive rewards or face on-chain penalties

When to Use PoA:

• Known participants that can be identified and vetted
• Existing trust relationships or legal frameworks
• Regulatory compliance requiring known validator identities
• Private networks for specific consortia
• High throughput requirements over decentralization

Validator Manager Contract

The Validator Manager Contract is the smart contract system that manages validator operations in permissioned L1s. It follows a two-phase commit pattern for all validator changes.

Core Functions:

Initialization:

• initializeValidatorSet(): Establishes initial validator set when converting Subnet to L1

Validator Lifecycle Management:

• initiateValidatorRegistration(): Starts adding a new validator
• completeValidatorRegistration(): Finalizes validator addition after P-Chain confirmation
• initiateValidatorRemoval(): Begins removing a validator
• completeValidatorRemoval(): Finalizes removal after P-Chain confirmation
• initiateValidatorWeightUpdate(): Changes validator voting weight
• completeValidatorWeightUpdate(): Finalizes weight changes

Key Features:

• All functions protected with onlyOwner modifier
• Two-phase commit pattern: initiate → complete
• Churn rate limiting to prevent rapid validator set changes
• Warp message construction and verification

P-Chain Integration

The Platform Chain (P-Chain) is the backbone for Avalanche's native interoperability. It serves as a registry of all validators in the network, including L1 validators.

How P-Chain Calls Work:

1. Validator Registration: When adding a validator, the contract initiates a P-Chain transaction
2. Warp Messages: Cross-chain communication uses Warp messages to interact with P-Chain
3. Confirmation Process: P-Chain processes the request and sends confirmation back
4. State Updates: The validator manager contract updates its state based on P-Chain confirmation

P-Chain Transaction Types:

• CreateSubnetTx: Creates new subnet for L1
• CreateChainTx: Creates new blockchain within subnet
• Validator registration/removal transactions
• Weight update transactions

Key Points:

• P-Chain is not EVM-based - requires compatible wallet like Core wallet
• L1 validators sync P-Chain but don't participate in its consensus
• All validator changes must be confirmed by P-Chain before taking effect
• P-Chain maintains the authoritative record of all validators across the network