Elevate user experience and security in React Native iOS app by seamlessly integrating Face ID authentication. This guide empowers you to leverage the power of biometrics, offering a convenient and secure login process for your users.

Why Use Face ID Authentication?

• Enhanced Security: Face ID offers a robust layer of protection compared to traditional passwords or PINs. It leverages unique facial features for user identification, making it more resistant to unauthorized access.
• Improved User Experience: Biometric authentication provides a seamless login experience, eliminating the need to remember and enter complex credentials. Users simply glance at their device, and voilà, they’re authenticated!

Challenges and Solutions

• Device Compatibility: Ensure your app targets devices with Face ID capabilities (iPhone X and later models).
• User Enrollment: Guide users through enabling Face ID in their device settings if it’s not already set up.
• Fallback Mechanism: Implement a fallback option like traditional login (email/password) in case Face ID is unavailable or the user encounters issues. This ensures a smooth experience even if Face ID encounters errors.
• Security Considerations: Store user credentials securely using a library like react-native-keychain. Never store raw data on the device.
• Clear User Communication: Inform users about how their Face ID data is used by your app through a detailed explanation in the NSFaceIDUsageDescription key within your iOS project’s Info.plist file. This transparency builds trust and encourages users to enable Face ID.

Implementation Steps

1. Project Setup:

• Install the react-native-biometrics library:

npm install react-native-keychain

• Install the react-native-keychain library:

npm install react-native-keychain

• Link native dependencies: cd ios && pod install.

• Add the NSFaceIDUsageDescription key to your iOS project’s Info.plist file and provide a clear explanation of how your app uses Face ID data.

2. Check Biometric Availability:

In your React Native component, use ReactNativeBiometrics.isSensorAvailable() to check if Face ID is present on the device.

Store the availability result in a state variable (e.g., biometricsAvailable) for conditional rendering.

const checkBiometrics = async () => {
  const rnBiometrics = new ReactNativeBiometrics();
  const isAvailable = await rnBiometrics.isSensorAvailable();

  if (isAvailable.available && isAvailable.biometryType == 'FaceID') {
    biometricsAvailable.current = isAvailable;
  }
};

3. Handle Login:

• Implement a traditional login flow using email/password or other credentials.
• Upon successful login, securely store the credentials in the keychain using react-native-keychain.

const handleLogin = async () => {
  if (email && password) {
    await storeCredentialsInSecureStorage({email, password});
    setModalMessage('Login successful');
    setShowModal(true);
  }
};

4. Handle Biometric Authentication:

• Create a function to handle Face ID login using ReactNativeBiometrics.simplePrompt().
• Provide a clear prompt message (e.g., “Authenticate using Face ID”).
• Handle success and failure scenarios:
• On success, display a success message or navigate to the appropriate app section.
• On failure, provide informative error messages and offer a fallback option (e.g., traditional login).

const handleBioAuth = async () => {
  try {
    const credentials = await retrieveCredentialsFromSecureStorage();

    if (!credentials) {
      setError('No credentials stored for biometric login.');
      return;
    }

    const rnBiometrics = new ReactNativeBiometrics();
    const {success} = await rnBiometrics.simplePrompt({
      promptMessage: 'Authenticate using biometrics',
    });

    if (success) {
      setModalMessage('Biometric authentication successful');
      setShowModal(true);
    } else {
      setModalMessage('Biometric authentication failed');
      setShowModal(true);
    }
  } catch (error) {
    console.error('Error during biometric authentication:', error);
    setModalMessage('An error occurred during biometric authentication.');
    setShowModal(true);
  }
};

Source code on Git hub:
biometric-auth-react-native

By following these steps and considerations, you can seamlessly integrate Face ID authentication into your React Native iOS app, enhancing both security and user experience.

Don’t Stop There:

While Face-ID authentication provides a robust solution for iOS devices, don’t limit yourself to one platform. Explore opportunities to extend biometric authentication to other platforms, such as Android, to provide a consistent user experience across different devices.