constant_device_id

A Flutter plugin that provides a permanent device identifier that persists across app reinstalls.

On Android, the identifier is derived from the hardware-level Widevine DRM ID a cryptographically unique value bound to the device at manufacture time. On iOS, the identifier is stored in the system Keychain, which Apple preserves across app reinstalls by default.

Features

Survives app uninstall and reinstall on both platforms
Hardware backed on Android via Widevine DRM (L1 / L3)
Keychain backed on iOS no extra configuration required
SHA-256 hashed output raw hardware IDs are never exposed
Four layer fallback for maximum reliability on edge case devices
No Android permissions required
Android 5.0+ (API 21) and iOS 12.0+ support

How It Works

ConstantDeviceId.getId() resolves the identifier through four layers in order, returning as soon as one succeeds:

Layer	Source	Survives Reinstall	Platform
0	Widevine DRM hardware ID	✅ Yes (until factory reset)	Android only
1	Secure Storage / iOS Keychain	✅ Yes (iOS) / ❌ No (Android)	Both
2	SharedPreferences	❌ No	Both
3	Generated UUID v4	❌ No	Both

On a normal Android device Layer 0 is always reached, making the ID truly permanent. On iOS, Layer 1 (Keychain) natively persists across reinstalls so the ID is equally stable.

Installation

Add the dependency to your pubspec.yaml:

dependencies:
  constant_device_id: ^0.1.0

Then fetch packages:

flutter pub get

Platform Setup

Android

No additional setup is required. The Widevine DRM API does not need any AndroidManifest.xml permissions.

Minimum SDK: 21 (Android 5.0 Lollipop)

iOS

No additional setup is required. The plugin uses flutter_secure_storage under the hood, which uses the iOS Keychain with first_unlock accessibility — items are retained after an app is deleted and reinstalled.

Minimum iOS version: 12.0

Usage

Get the permanent device ID

import 'package:constant_device_id/constant_device_id.dart';

final String deviceId = await ConstantDeviceId.getId();
print(deviceId);
// e.g. "a3f2c1d4e5b6f7a8b9c0d1e2f3a4b5c6d7e8f9a0b1c2d3e4f5a6b7c8d9e0f1a2"

The returned value is a 64-character lowercase hex string (SHA-256 hash), consistent across every call on the same device.

Reset locally stored ID

await ConstantDeviceId.reset();

Clears the ID from Secure Storage and SharedPreferences. On Android, the next call to getId() still returns the same hardware-derived ID because the Widevine layer is not affected by this operation.

API Reference