Upgradable Interface for Mina zkApps

Upgrade Authority Contract

The Upgrade Authority Contract provides a secure mechanism for upgrading the verification keys of smart contracts without requiring redeployment. It manages a list of validators who can vote on upgrade proposals, ensuring that only authorized upgrades are applied.

Key Features

• Verification Key Management: Allows for secure upgrades of verification keys for other contracts.
• Validators Governance: Maintains a list of authorized validators who can vote on upgrade proposals.
• Secure Voting Mechanism: Implements Zero-Knowledge proofs to validate votes from validators without revealing sensitive information.
• Upgrade Database Management: Keeps track of upgrade proposals and their validity periods.
• Event Emissions: Emits events when validators list or upgrade database is updated.

State Variables

• verificationKeyHash: The hash of the proof verification key (Field).
• validators: The hash representing the current state of the validators list (Field).
• upgradeDatabasePacked: Packed state containing the upgrade database information (UpgradeDatabaseStatePacked).

Key Methods

class VerificationKeyUpgradeAuthority extends SmartContract implements UpgradeAuthorityBase {
  @method
  async initialize(validators: ValidatorsState, storage: Storage, verificationKeyHash: Field) {
    // Initialize the contract with validators and set the verification key hash
  }

  @method.returns(UpgradeAuthorityAnswer)
  async verifyUpgradeData(data: VerificationKeyUpgradeData): Promise<UpgradeAuthorityAnswer> {
    // Verify the upgrade data provided by another contract
  }

  @method
  async updateDatabase(proof: ValidatorsVotingProof, vk: VerificationKey) {
    // Update the upgrade database after validator consensus
  }

  @method
  async updateValidatorsList(validators: ValidatorsState, storage: Storage, proof: ValidatorsVotingProof, vk: VerificationKey) {
    // Update the validators list based on validator votes
  }

  // ... Additional methods and helper functions
}

Events

• validatorsList: Emitted when the validators list is updated.
• updateDatabase: Emitted when the upgrade database is updated.

Notes

• Validator Governance: Validators can vote on upgrade proposals. The contract uses Zero-Knowledge proofs (ZkPrograms) to verify validator votes securely.
• Upgrade Process: Contracts wishing to upgrade their verification keys interact with the Upgrade Authority Contract to verify that the new verification key is authorized.
• Validators List Management: The validators list is stored as a Merkle Tree for efficient verification and can be updated through consensus.
• Off-chain Data: Some data, like the full validators list, is stored off-chain (e.g., in IPFS) with only the root hash stored on-chain to optimize performance.
• Security: The contract ensures that only valid upgrade proposals that have been approved by the required number of validators are executed.

Usage Example

This contract is essential for scenarios where:

• Decentralized Governance: Multiple validators need to agree on contract upgrades, ensuring no single party can unilaterally upgrade the contract.
• Secure Contract Upgrades: Contracts can securely upgrade their verification keys without redeploying, maintaining continuity and state.
• Regulated Environments: Applications requiring compliance and oversight can leverage validator governance for contract changes.

For a contract to utilize the Upgrade Authority Contract, it needs to implement the UpgradableContract interface and interact with the VerificationKeyUpgradeAuthority for upgrading its verification key securely.