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4.1.7 AggchainBase

AggchainBase

1. Core Initialization

1.1 initAggchainManager

Purpose: Sets the aggchain manager during rollup deployment.
Access Control: Only callable by the rollup manager. 

function initAggchainManager(address newAggchainManager) external onlyRollupManager

Parameters:

  • newAggchainManager: Address of the aggchain manager (cannot be zero address)

Event Emitted: 

event AcceptAggchainManagerRole(address indexed oldAggchainManager, address indexed newAggchainManager);

2. Aggchain Hash Computation

2.1 getAggchainHash

Purpose: Computes the aggchain hash for pessimistic proof verification.
Access Control: External view function (called by rollup manager). 

function getAggchainHash(bytes memory aggchainData) external view returns (bytes32)

Process: 1. Retrieves signers hash (from gateway if useDefaultSigners is true, otherwise local) 2. Calls getVKeyAndAggchainParams to extract vkey and params 3. Computes hash as: 

keccak256(
    CONSENSUS_TYPE ||      // 32 bits
    aggchainVKey ||        // 256 bits  
    aggchainParams ||      // 256 bits
    signersHash            // 256 bits
)

Returns: - Aggchain hash combining consensus type, verification key, parameters, and signers hash

2.2 getVKeyAndAggchainParams (Abstract)

Purpose: Extract verification key and parameters from aggchain data.
Implementation: Must be implemented by inheriting contracts. 

function getVKeyAndAggchainParams(bytes memory aggchainData) 
    public view virtual returns (bytes32 aggchainVKey, bytes32 aggchainParams)

3. Multisig Management

3.1 updateSignersAndThreshold

Purpose: Batch update signers and threshold in a single transaction.
Access Control: Only callable by aggchain manager. 

function updateSignersAndThreshold(
    RemoveSignerInfo[] memory _signersToRemove,
    SignerInfo[] memory _signersToAdd,
    uint256 _newThreshold
) external onlyAggchainManager

Parameters:

  • _signersToRemove: Array of signers to remove (must be in descending index order)
  • _signersToAdd: Array of new signers to add with URLs
  • _newThreshold: New threshold value

Event Emitted: 

event SignersAndThresholdUpdated(
    address[] aggchainSigners, 
    uint256 threshold, 
    bytes32 aggchainSignersHash
);

4. Getters and Setters

Important Note: All getter functions below will use gateway values if the corresponding useDefault* flag is enabled, otherwise they use local storage values.

4.1 Verification Key Functions

getAggchainVKey: Returns verification key - If useDefaultVkeys = true: Returns from aggLayerGateway.getDefaultAggchainVKey() - If useDefaultVkeys = false: Returns from local ownedAggchainVKeys mapping

addOwnedAggchainVKey / updateOwnedAggchainVKey: Manage local verification keys
Access Control: Only callable by aggchain manager

enableUseDefaultVkeysFlag / disableUseDefaultVkeysFlag: Toggle gateway vkeys usage
Access Control: Only callable by aggchain manager

4.2 Signer Functions

isSigner: Check if address is a signer - If useDefaultSigners = true: Queries aggLayerGateway.isSigner() - If useDefaultSigners = false: Checks local signerToURLs mapping

getAggchainSigners: Get all signer addresses - If useDefaultSigners = true: Returns from aggLayerGateway.getAggchainSigners() - If useDefaultSigners = false: Returns local aggchainSigners array

getAggchainSignersCount: Get number of signers - If useDefaultSigners = true: Returns from aggLayerGateway.getAggchainSignersCount() - If useDefaultSigners = false: Returns aggchainSigners.length

getAggchainSignersHash: Get signers configuration hash - If useDefaultSigners = true: Returns from aggLayerGateway.getAggchainSignersHash() - If useDefaultSigners = false: Returns local aggchainSignersHash

getAggchainSignerInfos: Get signers with URLs - If useDefaultSigners = true: Returns from aggLayerGateway.getAggchainSignerInfos() - If useDefaultSigners = false: Builds array from local storage

enableUseDefaultSignersFlag / disableUseDefaultSignersFlag: Toggle gateway signers usage
Access Control: Only callable by aggchain manager

4.3 Aggchain Manager Functions

transferAggchainManagerRole: Initiate two-step role transfer
acceptAggchainManagerRole: Complete role transfer
Access Control: Transfer by current manager, accept by pending manager

4.4 Utility Functions

getAggchainVKeySelector: Combine vkey version and type into selector
getAggchainTypeFromSelector: Extract type from selector
getAggchainVKeyVersionFromSelector: Extract version from selector

5. Constants and Architecture

5.1 Key Constants

  • CONSENSUS_TYPE = 1: Generic aggchain hash support identifier
  • Maximum 255 signers supported

5.2 Abstract Contract Design

  • AggchainBase is an abstract contract providing common functionality
  • Inheriting contracts must implement getVKeyAndAggchainParams
  • Each implementation defines its own AGGCHAIN_TYPE constant

5.3 Gateway Integration

  • Verification keys and signers can be managed locally or via gateway
  • Gateway functions don't check flags - flag validation happens in aggchain contracts
  • Provides flexibility for chains to use shared or custom configurations