fisherBridgeReceive

Function Type: external
Function Signature: fisherBridgeReceive(address,address,address,uint256,uint256,bytes)
Access Control: onlyFisherExecutor
Returns: void

Receives Fisher bridge transactions from external chain and credits EVVM balances. Verifies EIP-191 signature, increments nonce, and adds balance to recipient and executor for priority fees.

Parameters

Parameter	Type	Description
from	address	Original sender on the external chain
addressToReceive	address	Recipient address for the EVVM balance credit
tokenAddress	address	Token contract address or address(0) for native coin
priorityFee	uint256	Fee amount paid to the fisher executor
amount	uint256	Amount to credit to the recipient's EVVM balance
signature	bytes	Cryptographic signature (EIP-191) from the from address authorizing this transaction.

Access Control

This function can only be called by addresses with the fisherExecutor role:

modifier onlyFisherExecutor() {
    if (msg.sender != fisherExecutor.current) {
        revert();
    }
    _;
}

Workflow

1. Signature Verification

if (!SignatureUtils.verifyMessageSignedForFisherBridge(
    EVVM_ID,
    from,
    addressToReceive,
    nextFisherExecutionNonce[from],
    tokenAddress,
    priorityFee,
    amount,
    signature
)) revert ErrorsLib.InvalidSignature();

Validates EIP-191 signature using structured message format with EVVM ID integration. Message format: "{EVVM_ID},fisherBridge,{addressToReceive},{nonce},{tokenAddress},{priorityFee},{amount}".

2. Nonce Management

nextFisherExecutionNonce[from]++;

Increments user's Fisher bridge nonce to prevent replay attacks across cross-chain operations.

3. EVVM Balance Updates

Recipient Credit

Evvm(evvmAddress).addAmountToUser(addressToReceive, tokenAddress, amount);

Adds the transfer amount to recipient's EVVM balance via core contract integration.

Fisher Executor Fee

if (priorityFee > 0) {
    Evvm(evvmAddress).addAmountToUser(msg.sender, tokenAddress, priorityFee);
}

Credits priority fee to Fisher executor's EVVM balance as processing incentive.

Signature Message Format

info

For more information about the signature structure, refer to the Fisher Bridge Signature Structure.

EVVM Integration

The function directly integrates with the EVVM core contract for balance management:

Evvm(evvmAddress).addAmountToUser(addressToReceive, tokenAddress, amount);

This provides:

• Direct Balance Credit: Adds tokens to user's EVVM virtual balance
• Token Type Support: Handles both ERC20 tokens and native ETH (address(0))
• Atomic Operations: Ensures consistent state between Treasury and EVVM core
• Fee Distribution: Separates user funds from Fisher executor incentives

Security Features

• Fisher Executor Authorization: onlyFisherExecutor modifier restricts function access
• EIP-191 Signature Verification: Structured message format with EVVM ID binding
• Nonce-Based Replay Protection: Sequential nonce tracking per user address
• EVVM ID Integration: Cross-instance security through unique identifiers
• Balance Segregation: Separate handling of transfer amount and priority fees

Cross-Chain Flow

1. External Chain: User initiates Fisher bridge transaction with signature
2. Fisher Monitoring: Fisher executor captures transaction from external station
3. Host Chain Processing: This function validates and credits EVVM balances
4. Balance Availability: Tokens immediately available in user's EVVM account } }

## Fisher Bridge Benefits

### For Users
- **Gasless Transactions**: Users don't need native tokens on the host chain
- **Flexible Recipients**: Can specify different recipient addresses
- **Signature-based Authorization**: Secure consent without direct interaction

### For Fisher Executors
- **Priority Fees**: Earn fees for facilitating transfers
- **Batch Processing**: Can process multiple transfers efficiently
- **Automated Operations**: Enable programmatic cross-chain services

## Security Features

### Signature Security
- **EIP-191 Standard**: Uses Ethereum's signed message standard (see [signature format](../../../14-SignatureStructures/04-Treasury/01-FisherBridgeSignatureStructure.md))
- **Replay Protection**: Nonce-based prevention of signature reuse
- **Address Binding**: Signature tied to specific sender address

### Access Control
- **Fisher Authorization**: Only authorized executors can call the function
- **Signature Validation**: Cryptographic proof of user consent required (see [signature format](../../../14-SignatureStructures/04-Treasury/01-FisherBridgeSignatureStructure.md))

### Balance Management
- **Direct EVVM Integration**: Secure balance updates through authorized treasury functions
- **Atomic Operations**: Balance credits are processed atomically

## Error Conditions

| Error | Condition |
|-------|-----------|
| `InvalidSignature` | Signature verification fails |
| Access Control Revert | Called by unauthorized address (not current fisher executor) |

## Usage Example

A typical fisher bridge receive flow:

1. User signs a message on external chain authorizing the transfer
2. Fisher executor receives the signature and transfer details
3. Fisher calls `fisherBridgeReceive` with the signature and transfer parameters
4. Function validates signature and credits EVVM balances
5. User receives tokens in EVVM, fisher receives priority fee (if applicable)

:::info[Fisher Executor Management]
Fisher executors are managed through a time-delayed governance system. See [Admin Functions](./05-AdminFunctions.md) for details on executor management.
:::