Password management has always been a headache. Remembering complex passwords, dealing with password resets, and securing sensitive data—these tasks can be cumbersome and insecure. Enter passkeys and WebAuthn, the future of passwordless authentication. These technologies promise to simplify user authentication while enhancing security. In this post, I’ll walk you through the challenges, solutions, and practical implementation steps.
The Problem: Password Fatigue and Security Risks
Traditional password-based systems suffer from several issues:
- Complexity: Users struggle to create and remember strong passwords.
- Reusability: Many people reuse passwords across multiple sites, increasing risk.
- Phishing: Attackers often exploit weak passwords through phishing attacks.
- Credential Stuffing: Automated attacks using leaked credentials.
These problems highlight the need for a more secure and user-friendly authentication method. Passkeys and WebAuthn address these issues by providing a passwordless solution.
Understanding Passkeys and WebAuthn
What Are Passkeys?
Passkeys are a type of cryptographic key pair stored in a user’s device (such as a smartphone or computer). Unlike traditional passwords, passkeys are unique to each user and service combination. They eliminate the need for remembering passwords and reduce the risk of phishing attacks.
What Is WebAuthn?
Web Authentication (WebAuthn) is a W3C standard that enables strong, passwordless authentication. It allows websites to verify users’ identities using public key cryptography instead of passwords. WebAuthn supports various authenticators, including biometric sensors, hardware tokens, and software tokens.
How Do They Work Together?
Passkeys leverage WebAuthn to authenticate users securely. When a user registers for a service, their device generates a public-private key pair. The private key remains on the device, while the public key is sent to the server. During login, the device uses the private key to sign a challenge from the server, proving the user’s identity.
Implementing Passkeys with WebAuthn
Let’s dive into the practical aspects of implementing passkeys using WebAuthn. We’ll cover registration, authentication, and common pitfalls.
Registration Process
The registration process involves creating a passkey on the user’s device and storing the public key on the server.
Step-by-Step Guide
Create a credential creation options object
The server generates a challenge and sends it to the client.Invoke the navigator.credentials.create() method
The client prompts the user to select an authenticator (e.g., fingerprint sensor).Handle the response
The client receives the public key and sends it back to the server.Store the public key
The server stores the public key and associates it with the user.Example Code
Here’s a simplified example using JavaScript:
// Server-side: Generate challenge and send to client
const challenge = Buffer.from(crypto.randomBytes(32)).toString('base64url');
res.json({ challenge });
// Client-side: Create credential
navigator.credentials.create({
publicKey: {
rp: {
name: "Example Corp",
id: "example.com"
},
user: {
id: Buffer.from(user.id).toString('base64url'),
name: user.email,
displayName: user.name
},
challenge: Buffer.from(challenge, 'base64url'),
pubKeyCredParams: [{ alg: -7, type: "public-key" }]
}
}).then((credential) => {
// Send response to server
fetch('/register', {
method: 'POST',
headers: { 'Content-Type': 'application/json' },
body: JSON.stringify({
id: credential.id,
rawId: Buffer.from(credential.rawId).toString('base64url'),
response: {
attestationObject: Buffer.from(credential.response.attestationObject).toString('base64url'),
clientDataJSON: Buffer.from(credential.response.clientDataJSON).toString('base64url')
},
type: credential.type
})
});
});
// Server-side: Verify response and store public key
const attestation = await navigator.credentials.parseAttestationObject(req.body.response.attestationObject);
const publicKey = attestation.authenticatorInfo.credentialPublicKey;
await storePublicKey(user.id, publicKey);
Authentication Process
The authentication process verifies the user’s identity using the passkey stored on their device.
Step-by-Step Guide
Create an assertion request object
The server generates a challenge and sends it to the client.Invoke the navigator.credentials.get() method
The client prompts the user to select an authenticator.Handle the response
The client sends the signed challenge back to the server.Verify the signature
The server verifies the signature using the stored public key.Example Code
Here’s a simplified example using JavaScript:
// Server-side: Generate challenge and send to client
const challenge = Buffer.from(crypto.randomBytes(32)).toString('base64url');
res.json({ challenge });
// Client-side: Get assertion
navigator.credentials.get({
publicKey: {
challenge: Buffer.from(challenge, 'base64url'),
allowCredentials: [{
id: Buffer.from(publicKeyId).toString('base64url'),
type: "public-key",
transports: ["internal"]
}]
}
}).then((assertion) => {
// Send response to server
fetch('/authenticate', {
method: 'POST',
headers: { 'Content-Type': 'application/json' },
body: JSON.stringify({
id: assertion.id,
rawId: Buffer.from(assertion.rawId).toString('base64url'),
response: {
authenticatorData: Buffer.from(assertion.response.authenticatorData).toString('base64url'),
clientDataJSON: Buffer.from(assertion.response.clientDataJSON).toString('base64url'),
signature: Buffer.from(assertion.response.signature).toString('base64url')
},
type: assertion.type
})
});
});
// Server-side: Verify response
const clientData = JSON.parse(Buffer.from(req.body.response.clientDataJSON, 'base64url'));
const authenticatorData = Buffer.from(req.body.response.authenticatorData, 'base64url');
const signature = Buffer.from(req.body.response.signature, 'base64url');
const verified = await navigator.credentials.verifySignature({
publicKey,
authenticatorData,
clientDataJSON: clientData,
signature
});
if (verified) {
// Authentication successful
} else {
// Authentication failed
}
Common Pitfalls and Solutions
Implementing passkeys and WebAuthn can be tricky. Here are some common pitfalls and solutions:
- Incorrect Challenge Handling: Ensure challenges are correctly generated and verified. Use a secure random number generator.
- Cross-Origin Issues: WebAuthn requires the same origin policy. Ensure your frontend and backend are served from the same domain.
- Authenticator Compatibility: Not all devices support WebAuthn. Test on various devices and browsers.
- Error Handling: Properly handle errors to provide meaningful feedback to users.
🎯 Key Takeaways
- Passkeys and WebAuthn offer a secure, passwordless authentication method.
- Implement registration and authentication processes carefully to ensure security.
- Test on various devices and browsers to ensure compatibility.
Comparing Passkeys and Traditional Passwords
| Approach | Pros | Cons | Use When |
|---|---|---|---|
| Passkeys & WebAuthn | No password reuse, reduced phishing risk | Requires compatible devices, initial setup complexity | Modern web applications |
| Traditional Passwords | Simple to implement, widely supported | Password fatigue, high risk of phishing | Legacy systems |
Security Considerations
When implementing passkeys and WebAuthn, consider the following security best practices:
- Secure Storage: Store public keys securely using encryption.
- Challenge Validation: Always validate challenges to prevent replay attacks.
- Error Handling: Provide clear error messages without revealing sensitive information.
- Regular Audits: Conduct regular security audits and updates.
Real-World Examples
Several major companies have adopted passkeys and WebAuthn:
- Microsoft: Uses passkeys for Microsoft 365 and Azure.
- Apple: Supports passkeys in Safari and iCloud.
- Google: Implements passkeys in Chrome and Google Accounts.
These examples demonstrate the growing adoption and effectiveness of passkeys and WebAuthn.
Conclusion
Passkeys and WebAuthn represent a significant advancement in authentication technology. By eliminating passwords, they enhance security and improve user experience. Implementing these technologies requires careful planning and testing, but the benefits are well worth the effort.
Go ahead and give passkeys a try. Your users will thank you for it.