Passwordless Authentication Options

TL;DR

Yes! Lots of web services now use alternatives to passwords for logging in – things like one-time codes sent by email or text, biometric scans (fingerprint, face ID), security keys, and magic links. This guide explains the main options and how they work.

What are Passwordless Authentication Methods?

Passwordless authentication aims to get rid of traditional passwords altogether, or at least reduce reliance on them. Here’s a breakdown of common methods:

1. One-Time Passcodes (OTP) via Email/SMS: This is very common.
   • A code is sent to your registered email address or mobile phone number when you try to log in.
   • You enter the code alongside your username (often an email).
   • Security Level: Moderate – SMS can be intercepted, and email accounts are vulnerable.
2. Authenticator Apps (TOTP): Like Google Authenticator or Authy.
   • These apps generate time-based one-time passwords that change every 30 seconds or so.
   • You scan a QR code during setup to link the app to the service.
   • Security Level: High – More secure than SMS OTP as codes aren’t sent over networks. Requires protecting your phone.
3. Biometric Authentication: Fingerprint, face ID, or voice recognition.
   • Uses the sensors on your device (phone, laptop) to verify your identity.
   • Often integrated with WebAuthn/Passkeys (see below).
   • Security Level: High – Very convenient but relies on the security of the device’s biometric system.
4. Security Keys (FIDO2/WebAuthn): Physical USB keys or built-in platform authenticators.
   • These create a cryptographic key pair – one part stays on the key, the other with the service.
   • When you log in, the key proves your identity without sending a password.
   • Security Level: Very High – Resistant to phishing and man-in-the-middle attacks.
5. Magic Links:
   • A unique link is emailed to you when you try to log in. Clicking the link logs you in automatically.
   • Security Level: Moderate – Vulnerable if your email account is compromised, but better than passwords.

How do these methods work technically?

Here’s a simplified look at some of the underlying tech:

1. OTP (Email/SMS): The service generates a random code and sends it to your registered contact method. The service verifies this code against what was sent when you attempt login.
2. TOTP: Uses the RFC 6238 standard algorithm, which combines a secret key with the current time to generate codes. The service verifies this code against what it calculates.
3. WebAuthn (FIDO2): A web API that allows websites to use strong authentication methods like security keys and platform authenticators. It uses public-key cryptography for secure verification.

   // Example JavaScript snippet showing WebAuthn availability

   if (navigator.credentials) {
     navigator.credentials.create({
       publicKey: {
         challenge: challenge,
         rpId: 'example.com'
       }
     })
     .then(credential => { ... });
   }

Examples of Services Using Passwordless Authentication

• Google: Offers phone sign-in (OTP), Google Prompt, and Passkeys.
• Microsoft: Supports Microsoft Authenticator app, Windows Hello (biometrics), and FIDO2 security keys.
• Apple: Uses Face ID/Touch ID for Apple Pay and iCloud logins, plus Passkeys.
• LastPass/1Password: Password managers often support OTP and authenticator apps.

Is Passwordless Authentication More Secure?

Generally, yes. It reduces the risk of:

• Phishing Attacks: Many methods don’t rely on you typing anything into a website.
• Password Reuse: You’re not using the same password across multiple sites.
• Data Breaches: Passwords aren’t stored in plain text (or at all, with WebAuthn).

However, it introduces new risks like losing access to your phone or security key.