dart_web3_keystone

A high-security interface for Keystone hardware wallets. Fully supports air-gapped communication via the BC-UR protocol for Ethereum and multi-chain signing workflows.

🚀 Features

• Air-Gapped QR Connect: Complete implementation of Keystone's multi-part QR protocol.
• Signature Verification: Parse and verify Keystone-signed Ethereum transactions and messages.
• Multi-Account Sync: Efficiently sync hundreds of derived accounts from a single Keystone QR scan.
• Safe Multisig: Specialized support for Keystone-based multisig wallet configurations.

Usage Flow

sequenceDiagram
    participant A as App
    participant K as Keystone Device
    A->>A: build Transaction
    A->>A: encode as BC-UR frames
    A-->>A: display animated QR
    K->>A: scan QR from screen
    K-->>K: verify & sign
    K-->>K: display result QR
    A->>K: scan signature from device
    A->>A: reconstruct & verify

🏗️ Architecture

graph LR
    DApp[Dart / Flutter] --> Scanner[Camera/Scanner]
    Scanner --> UR[BC-UR Decoder]
    UR --> Keystone[Keystone Client]
    Keystone --> UI[App State]
    
    UI --> Encoder[BC-UR Encoder]
    Encoder --> Screen[Generated QR]
    Screen --> Camera[Keystone Camera]

📚 Technical Reference

Core Classes

🛡️ Security Considerations

• Verify on Screen: Always instruct users to verify the transaction details (Recipient, Amount, Fee) on the Keystone's physical screen.
• Air-Gapped Integrity: This module relies on dart_web3_bc_ur. Ensure no un-audited dependencies are injected into the transport layer.
• Key Extraction: Hardware wallets like Keystone are designed to never leak the private key; this SDK only handles public keys and signed payloads.

💻 Usage

Synchronizing Wallet Data

import 'package:dart_web3_keystone/dart_web3_keystone.dart';

void main() {
  final keystone = KeystoneClient();

  // 1. Scan the Sync QR from Keystone
  keystone.decodeSync(qrData);

  for (var account in keystone.accounts) {
    print('Derived Address: ${account.address}');
    print('Path: ${account.path}');
  }
}

📦 Installation

dependencies:
  dart_web3_keystone: ^0.1.0