Nitewatch

Nitewatch is a package used by NeoDAX to interact with an EVM on-chain custody contract through the ICustody interface. It provides the security policy engine and the infrastructure to manage deposits and withdrawals.

NeoDAX utilizes the Nitewatch package to run two primary processes:

1. Event Daemon: Produces ICustody events by listening to the blockchain and pushing them to an internal Message Queue (MQ).
2. Contract Interface: An implementation to call smart-contract methods (e.g., starting or finalizing withdrawals).

Stack

• Smart Contracts: Solidity (Forge)
• Backend: Go
• Blockchain: EVM-compatible chains

Features

Deposits

1. User deposits native ETH or ERC20 tokens into the custody contract via a frontend dApp.
2. The Event Daemon detects the on-chain event.
3. An internal event is fired to the NeoDAX MQ.
4. NeoDAX credits the user's balance.

Withdrawals

Withdrawals are governed by a security policy engine that tracks per-user and global limits (hourly/daily).

1. User requests a withdrawal via the NeoDAX Web API.
2. NeoDAX validates the request internally and locks the user's balance.
3. NeoDAX uses the Nitewatch package to call startWithdraw on the custody contract.
4. The Nitewatch Daemon listens for the WithdrawStarted event, applies the security policy, and then either calls finalizeWithdraw or rejectWithdraw.
5. The Event Daemon waits for the outcome (WithdrawFinalized or WithdrawRejected), fires an internal event, and NeoDAX debits the balance upon successful confirmation.

Flows

Withdrawal Flow

sequenceDiagram
    actor User
    participant NeoDAX as NeoDAX (API & MQ)
    participant NWPkg as Nitewatch Package
    participant Contract as Custody Contract
    participant NWDaemon as Nitewatch Daemon

    Note over User, NeoDAX: Request
    User->>NeoDAX: Request withdrawal
    NeoDAX->>NeoDAX: Validate & Lock balance
    
    Note over NWPkg, Contract: Initiation
    NeoDAX->>NWPkg: startWithdraw()
    NWPkg->>Contract: on-chain call
    Contract-->>NWDaemon: WithdrawStarted event

    Note over NWDaemon, Contract: Security Policy & Finalization
    NWDaemon->>NWDaemon: Apply Security Policy
    NWDaemon->>Contract: finalizeWithdraw() or rejectWithdraw()
    
    Note over NWPkg, NeoDAX: Confirmation
    Contract-->>NWPkg: WithdrawFinalized/Rejected event
    NWPkg->>NeoDAX: Fire internal MQ event
    NeoDAX->>NeoDAX: Debit balance (if finalized)

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