This package provide a means to authenticate a user with biometrics and securely cache sensitive information like password and tokens

On supported devices, this includes authentication with biometrics such as fingerprint or facial recognition.

Android iOS Windows
Support SDK 16+* 9.0+ Windows 10+


import 'package:local_biometrics_auth/local_biometrics_auth.dart';
// ···
  final BiometricsAuth auth =  BiometricsAuth.initialise();
  // ···
    final bool canUseBiometrics =  auth.canUseBiometrics;
    final bool isBiometricsSetup =  await auth.isBiometricsSetup;

You can authenticate users with the following option:

  • BiometricType.face
  • BiometricType.fingerprint

Enrolled Biometrics

canUseBiometrics only indicates if the device is capable of using any of the biometrics options.


The authenticate() method authenticates the user and returns true if authentication was successful.

you can set user authentication details(Password, token) after

try {
    await auth.authenticate().then((value) {
      if (value == BiometricsResponse.success) {
        auth.setAuthKey(authKey: AuthKey(key: authData));
  // ···
} catch(e) {
  // ...

Securely caching user data

  • Keychain is used for iOS
  • AES encryption is used for Android. AES secret key is encrypted with RSA and RSA key is stored in KeyStore

to save user details call auth.setAuthKey(authKey: AuthKey(key: authData))

Retrieving saved data;

  • This data can be fetched only after biometric authentication
    auth.authenticateAndGetAuthKey().then((value) {
      if (value?.key != null) {

Biometrics Only

To require biometric authentication only, set biometricsOnly to true when calling BiometricsAuth.initialise()

    auth = await BiometricsAuth.initialise(biometricsOnly: true);

Note: biometricOnly is not supported on Windows since the Windows implementation's underlying API (Windows Hello) doesn't support selecting the authentication method.

iOS Integration

Note that this plugin works with both Touch ID and Face ID. However, to use the latter, you need to also add:

<string>Why is my app authenticating using face id?</string>

to your Info.plist file. Failure to do so results in a dialog that tells the user your app has not been updated to use Face ID.

Android Integration

Activity Changes

Note that local_auth requires the use of a FragmentActivity instead of an Activity. To update your application:

  • If you are using FlutterActivity directly, change it to FlutterFragmentActivity in your AndroidManifest.xml.

  • If you are using a custom activity, update your MainActivity.java:

    import io.flutter.embedding.android.FlutterFragmentActivity;
    public class MainActivity extends FlutterFragmentActivity {
        // ...

    or MainActivity.kt:

    import io.flutter.embedding.android.FlutterFragmentActivity
    class MainActivity: FlutterFragmentActivity() {
        // ...

    to inherit from FlutterFragmentActivity.


Update your project's AndroidManifest.xml file to include the USE_BIOMETRIC permissions:

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
  <uses-permission android:name="android.permission.USE_BIOMETRIC"/>