esp_prov

Provision ESP32 devices over Bluetooth LE with Espressif's Unified Provisioning protocol. Security 0, 1 and 2 (SRP-6a + AES-GCM) are implemented in pure Dart; no native Espressif SDK is involved.

• Scans for PROV_ devices, connects, reads proto-ver and picks the security scheme the firmware declares.
• Wi-Fi scan and provisioning with typed progress states.
• Thread provisioning (network_provisioning firmware).
• Custom endpoints (custom-data in the ESP-IDF examples).
• Parses the provisioning QR payload printed by the firmware.

Usage

import 'package:esp_prov/esp_prov.dart';

Future<void> provision() async {
  final prov = EspProvisioning();
  final device = await prov.scan(namePrefix: 'PROV_').first;
  final session = await device.connect(
    credentials: const ProvCredentials.security2(
      username: 'wifiprov',
      password: 'abcd1234',
    ),
  );
  try {
    final networks = await session.wifi.scan();
    await for (final state in session.wifi.provision(
      ssid: networks.first.ssid,
      passphrase: 'my-passphrase',
    )) {
      switch (state) {
        case WifiConnected(:final ip4):
          print('Device joined the network as $ip4');
        case WifiFailed(:final reason):
          print('Provisioning failed: ${reason.name}');
        case WifiApplying() || WifiConnecting() || WifiAttemptFailed():
          break;
      }
    }
  } finally {
    await session.close();
  }
}

From a QR code string:

final qr = ProvQrPayload.parse(qrString);
final device = await EspProvisioning().findDevice(qr.name);
final session = await device.connect(credentials: qr.credentials);

The firmware chooses the security scheme (advertised through proto-ver); the app only supplies the matching credentials. After WifiConnected the device stops provisioning and disconnects on its own, so a following session.close() is harmless.

This package is an independent, pure-Dart alternative to the unmaintained flutter_esp_ble_prov (not a fork).

Errors

All failures are subclasses of the sealed ProvException: PopMismatch (wrong PoP or password), SchemeMismatch (credential kind does not match the firmware), MissingCredentials, DeviceDisconnected, TransportException, UnknownEndpoint, UnsupportedCapability, HandshakeFailed, CryptoException, ProvStatusException. Wrong Wi-Fi passphrase or unknown SSID are not exceptions: they arrive as WifiFailed(reason: WifiFailureReason.authError | networkNotFound). WifiFailureReason also has timeout and deviceDisconnected. Protocol faults (ProvException subclasses) arrive as stream errors on provision(), so callers should handle both states and errors.

Platform setup

This package does not request runtime permissions. Request them before scanning (for example with UniversalBle.requestPermissions() or permission_handler).

Android (android/app/src/main/AndroidManifest.xml):

<uses-permission android:name="android.permission.BLUETOOTH_SCAN" android:usesPermissionFlags="neverForLocation" />
<uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />
<uses-permission android:name="android.permission.BLUETOOTH" android:maxSdkVersion="30" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" android:maxSdkVersion="30" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" android:maxSdkVersion="28" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" android:maxSdkVersion="30" />

iOS and macOS (Info.plist): NSBluetoothAlwaysUsageDescription. macOS entitlements: com.apple.security.device.bluetooth.

Web: Web Bluetooth needs a user gesture to scan and only exposes services listed in UniversalBleScanner(webServiceUuids: ...). Some browsers cannot read characteristic descriptors; the standard endpoints still work through the UUID fallback, custom endpoints may not.

Security 2 performance

The SRP-6a handshake does 3072-bit modular exponentiation. On native platforms it runs on a background isolate; on the web it runs inline and takes noticeably longer.