Introduction

WebAuthn is a standardized API that empowers web applications to authenticate users using various biometric factors, including fingerprints. It offers a secure and platform-independent approach to user authentication, eliminating the need for traditional passwords.

Understanding WebAuthn

Provides a secure and reliable way to authenticate users without passwords.
Enables a consistent user experience across different platforms and devices.
Reduces the risk of unauthorized access due to compromised passwords.

Implementing Fingerprint Authentication with WebAuthn

1. Setting Up the Environment:

• Ensure your web application is served over HTTPS to safeguard sensitive data.
• Include the WebAuthn library or polyfill within your project.

2. Creating a Credential Creation Request:

• Generate a unique challenge value to thwart replay attacks.
• Define the desired authentication parameters, encompassing the user's ID and the relying party's information.
• Utilize the navigator.credentials.create() method to initiate the credential creation process.

3. Handling User Interaction:

• The browser will prompt the user to enroll their fingerprint.
• Upon successful enrollment, a credential will be generated.

4. Storing the Credential:

• Securely store the created credential on the server using encryption or hashing techniques.

5. Authenticating the User:

• When a user attempts to authenticate, send a credential request to the server.
• The server verifies the credential against the stored data.
• If the verification succeeds, the user is authenticated.

Code Example

async function createCredential() {
  const randomStringFromServer = "random-string-from-server";

  const publicKeyCredentialCreationOptions = {
    challenge: Uint8Array.from(randomStringFromServer, (c) =>
      c.charCodeAt(0)
    ),
    rp: {
      name: "Authentication Test",
      id: "<domain name>",
    },
    user: {
      id: Uint8Array.from("UZSL85T9AFC", (c) => c.charCodeAt(0)),
      name: "authtest",
      displayName: "Authentication Test",
    },
    pubKeyCredParams: [{ alg: -7, type: "public-key" }],
    authenticatorSelection: {
      authenticatorAttachment: "cross-platform",
    },
    timeout: 60000,
    attestation: "direct",
  };

  const credential = await navigator.credentials.create({
    publicKey: publicKeyCredentialCreationOptions,
  });

  console.log(credential);
}

async function authenticateUser() {
  const randomStringFromServer = "random-string-from-server";
  const challenge = Uint8Array.from(randomStringFromServer, (c) =>
    c.charCodeAt(0)
  );

  const rp = {
    name: "Authentication Test",
    id: "<domain name>",
  };

  const user = {
    id: Uint8Array.from("UZSL85T9AFC", (c) => c.charCodeAt(0)),
  };

  const pubKeyCredParams = [
    {
      type: "public-key",
      alg: -7,
    },
  ];

  const credParams = {
    publicKey: {
      rp,
      user,
      challenge,
      pubKeyCredParams,
      authenticatorSelection: {
        authenticatorAttachment: "cross-platform",
      },
    },
  };

  try {
    const credential = await navigator.credentials.get(credParams);

    // Verify the credential against the stored data
    console.log(credential);
  } catch (error) {
    console.error("Error authenticating user:", error);
  }
}

Please refer to the following guide for more info

https://webauthn.io/

Best Practices

• Security: Always store credentials securely to mitigate unauthorized access.
• User Experience: Provide clear instructions and feedback throughout the user authentication process.
• Browser Compatibility: Ensure your implementation works across different browsers and devices.
• Error Handling: Implement robust error handling to gracefully manage potential issues.

By adhering to these guidelines and leveraging WebAuthn, you can significantly enhance the security and convenience of your web applications by incorporating fingerprint authentication.

Additional Considerations

Consider user privacy implications when implementing biometric authentication.
Explore cross-browser compatibility testing tools to ensure a seamless user experience.
Conclusion

WebAuthn offers a powerful and secure approach to user authentication in web applications. This blog post has provided an introduction to WebAuthn and its implementation, along with valuable best practices. By integrating WebAuthn, you can elevate the security of your web applications and provide a more convenient user experience.