How does the concept of passwordless authentication via biometrics and hardware keys work?
Passwordless authentication is rapidly replacing traditional character combinations through the use of cryptographic key pairs tied to a specific device. Instead of transmitting a secret to a remote server, the system verifies the user locally on their own smartphone or computer. Such verification is usually performed using biometric fingerprint scanners, facial recognition, or physical hardware security keys.
At the core of this technology is a cryptographic key pair consisting of a public and a private component. The public key is stored on the internet resource's server and holds no value to attackers in the event of a database leak. The private key is securely protected inside a secure hardware module on the user's device and never leaves it. Access to the private key is unlocked exclusively after successful completion of local biometric authentication.
When a user needs to log into a site, the server sends a unique cryptographic challenge. The user's device signs this challenge with the secret private key and sends back proof of authenticity. Since the signature is generated anew for each individual session, intercepting it or repeating a replay attack becomes technically impossible. This completely eliminates the risks associated with phishing and guessing weak character combinations.
To implement such a system on the web application side, developers use standard web APIs supported by modern browsers and operating systems. The integration process requires server-side support for the WebAuthn and FIDO2 protocols. This makes it possible to accept confirmations from various platforms, including built-in smartphone modules and external USB keys.
The main benefits of transitioning to passwordless authentication include the following aspects.