withdraw

Function Type: external payable
Function Signature: withdraw(address,address,uint256,bytes1)
Returns: void

Withdraws tokens from EVVM balance and sends them to external chain via selected cross-chain protocol. This function validates balance, deducts from EVVM, and bridges via Hyperlane, LayerZero, or Axelar protocols.

Parameters

Parameter	Type	Description
toAddress	address	Recipient address on the external chain
token	address	Token contract address or address(0) for native coin
amount	uint256	Amount to withdraw
protocolToExecute	bytes1	Cross-chain protocol identifier (0x01, 0x02, or 0x03)

Protocol Identifiers

Value	Protocol	Description
0x01	Hyperlane	Uses Hyperlane mailbox for cross-chain messaging
0x02	LayerZero	Uses LayerZero endpoint for omnichain transfers
0x03	Axelar	Uses Axelar gateway for decentralized cross-chain communication

Workflow

Initial Validations

1. Principal Token Protection: Validates token is not the Principal Token (MATE) using core.getEvvmMetadata().principalTokenAddress. Reverts with Error.PrincipalTokenIsNotWithdrawable() if attempted.
2. Balance Verification: Confirms user has sufficient EVVM balance using core.getBalance(msg.sender, token). Reverts with Error.InsufficientBalance() if insufficient.
3. EVVM Balance Deduction: Calls core.removeAmountFromUser(msg.sender, token, amount) to deduct from user's virtual balance.

Protocol-Specific Execution

Hyperlane (0x01)

bytes memory payload = PayloadUtils.encodePayload(token, toAddress, amount);
uint256 quote = IMailbox(hyperlane.mailboxAddress).quoteDispatch(
    hyperlane.externalChainStationDomainId,
    hyperlane.externalChainStationAddress,
    payload
);
IMailbox(hyperlane.mailboxAddress).dispatch{value: quote}(
    hyperlane.externalChainStationDomainId,
    hyperlane.externalChainStationAddress,
    payload
);

• Payload Encoding: Uses PayloadUtils.encodePayload() for standardized message format
• Quote Calculation: Gets exact dispatch cost via IMailbox.quoteDispatch()
• Message Dispatch: Sends to external station via Hyperlane mailbox with proper gas payment

LayerZero (0x02)

bytes memory payload = PayloadUtils.encodePayload(token, toAddress, amount);
MessagingFee memory fee = _quote(
    layerZero.externalChainStationEid,
    payload,
    options,
    false
);
_lzSend(
    layerZero.externalChainStationEid,
    payload,
    options,
    MessagingFee(fee.nativeFee, 0),
    msg.sender
);

• Payload Encoding: Uses PayloadUtils.encodePayload() for consistent data structure
• Fee Quotation: Calculates exact messaging fee via _quote() function
• Omnichain Send: Dispatches via LayerZero V2 endpoint with proper fee handling

Axelar (0x03)

bytes memory payload = PayloadUtils.encodePayload(token, toAddress, amount);
IAxelarGasService(axelar.gasServiceAddress).payNativeGasForContractCall{
    value: msg.value
}(
    address(this),
    axelar.externalChainStationChainName,
    axelar.externalChainStationAddress,
    payload,
    msg.sender
);
gateway().callContract(
    axelar.externalChainStationChainName,
    axelar.externalChainStationAddress,
    payload
);

• Payload Encoding: Uses PayloadUtils.encodePayload() for cross-chain compatibility
• Gas Service Payment: Prepays execution gas to Axelar gas service contract
• Gateway Dispatch: Routes message through Axelar gateway with refund to sender

Payload Encoding

The function uses standardized payload encoding via PayloadUtils library:

bytes memory payload = PayloadUtils.encodePayload(token, toAddress, amount);

This creates a consistent format decoded on external chain station using:

(address token, address toAddress, uint256 amount) = PayloadUtils.decodePayload(payload);

The payload structure ensures:

1. Token identification: ERC20 contract address or address(0) for native coins
2. Recipient specification: Exact recipient address on external chain
3. Amount precision: Token amount in native decimals

Gas Requirements

Users must send sufficient native tokens with the transaction to cover:

• Hyperlane: Mailbox dispatch fees
• LayerZero: Endpoint messaging fees
• Axelar: Gas service payments

Gas Payment Required

The transaction will revert if insufficient native tokens are provided to cover cross-chain messaging costs. Use the respective quote functions to estimate required amounts.

Security Features

• User Authorization: Only holders can withdraw from their own EVVM balances
• Principal Token Protection: Error.PrincipalTokenIsNotWithdrawable() prevents MATE token withdrawal
• Balance Verification: Error.InsufficientBalance() protection with EVVM balance checks
• Protocol Validation: Reverts for invalid protocol identifiers
• Cross-Chain Security: Each protocol validates sender authorization on message receipt

External Chain Processing

Upon successful cross-chain message delivery, the External Chain Station:

1. Message Validation: Verifies sender authorization and chain ID
2. Payload Decoding: Uses PayloadUtils.decodePayload() to extract transfer details
3. Asset Transfer: Transfers ERC20 tokens or native coins to recipient
4. Event Emission: Logs successful cross-chain transfer for tracking