Passkey Authentication: A Modern Security Solution for Apps

Jan 10, 2025 4 min

Passkey Authentication: A Modern Security Solution for Apps

Passkeys are emerging as a revolutionary approach to eliminate vulnerabilities inherent to traditional passwords. In this blog, we’ll…

Passkey Authentication: A Modern Security Solution for Apps

Passkeys are emerging as a revolutionary approach to eliminate vulnerabilities inherent to traditional passwords. In this blog, we’ll explore how passkeys work, implement a proof of concept using Golang and React, and analyze how this solution can extend to mobile applications built with Flutter.

What Are Passkeys?

Passkeys replace traditional passwords with a cryptographic model based on public-private key pairs:

  • Private Key: Stored securely on the user’s device (e.g., phone or computer).
  • Public Key: Stored on the server to verify the authenticity of requests.

This interaction ensures robust authentication, mitigating common risks like phishing, brute force attacks, or weak password reuse.

How Passkey Authentication Works

  1. Initial Registration:
  • The server generates a unique challenge.
  • The client signs this challenge with its private key and sends the response to the server.
  • The server validates the signature using the public key and registers the user.

2. Authentication:

  • The server issues a new challenge.
  • The client signs it with the private key.
  • The server validates the signature to confirm the user’s identity.

Proof of Concept: Backend in Golang and Frontend in React

We covered the basic implementation in the previous section. Now, let’s extend the flow to integrate it into a mobile application using Flutter.

Extending to Flutter

Why Use Flutter for Passkeys?

Flutter is an excellent choice for mobile apps with passkeys due to:

  1. Cross-platform compatibility: Develop a single codebase for both Android and iOS.
  2. WebAuthn support: Flutter can interact with WebAuthn through native libraries or plugins.
  3. Seamless biometric integration: Leverage native APIs for fingerprint and face authentication.

Passkey Integration in Flutter

Step 1: Backend Ready for Mobile Applications

The Golang backend is already WebAuthn-compliant. Ensure proper domain setup (RPID and origin) to include:

  • https://yourmobileapp.com for production.
  • http://localhost for local testing.

Step 2: Flutter Configuration

  • Install Necessary Dependencies: Use the flutter_webauthn package (or similar):

dependencies:
flutter_webauthn: ^1.0.0

  • Register Users with Passkeys:

import ‘package:flutter_webauthn/flutter_webauthn.dart’;

Future<void> registerPasskey() async {
final options = await fetch(‘/register’);
final webAuthn = WebAuthn();
final credential = await webAuthn.createCredential(options);
await sendToServer(‘/register’, credential);
}

  • Authenticate Users:

import ‘package:flutter_webauthn/flutter_webauthn.dart’;

Future<void> authenticatePasskey() async {
final options = await fetch(‘/authenticate’);
final webAuthn = WebAuthn();
final credential = await webAuthn.getCredential(options);
final response = await sendToServer(‘/authenticate’, credential);
if (response.success) {
print(‘Authentication successful!’);
}
}

  • UI Design:

Flutter makes it easy to create an intuitive UI. Use widgets like ElevatedButton to trigger registration and authentication actions.

ElevatedButton(
onPressed: registerPasskey,
child: Text(‘Register Passkey’),
);

ElevatedButton(
onPressed: authenticatePasskey,
child: Text(‘Authenticate’),
);

Challenges in Implementing Passkeys in Flutter

  1. Browser Compatibility: Some platforms may lack full WebAuthn support, requiring alternative solutions for older devices.
  2. Complex Initial Setup: Properly configuring the backend for secure mobile applications can be challenging.
  3. Native Biometric Support: Flutter must interact with specific APIs to handle biometric sensors, occasionally requiring native code for iOS or Android.

Conclusion

Passkey authentication represents a significant shift in how we handle application security.

Advantages:

  • Strong security: Reduces risks from password-related attacks.
  • Enhanced user experience: Simplifies login processes, especially for mobile apps.
  • Future-proof: Aligns with the latest security standards.

Practical Applications:

  • Fintech: Secure authentication for transactions and financial operations.
  • E-commerce: Fast, secure login for shopping platforms.
  • Corporate apps: Extra protection for remote work environments.

Final Thoughts:

Integrating passkeys into Flutter expands possibilities, enabling functionality across web and mobile platforms. However, careful planning and thorough testing are essential to ensure a seamless experience.

Are you ready to bring passkey authentication to your next application?

By Jaime Hernández on January 10, 2025.

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Exported from Medium on March 15, 2025.

~devjaime