A passkey is a modern, passwordless authentication method that uses public-key cryptography to securely log users into their online accounts. Instead of relying on traditional passwords that can be stolen or phished, passkeys use a pair of cryptographic keys: a public key stored on the service's server and a private key securely stored on the user's device. Authentication is done by verifying the user via biometrics (like fingerprint or face recognition) or a device PIN, making it more secure and convenient.

How Passkeys Work

• When a user registers with a service that supports passkeys, their device generates a public-private key pair.
• The private key remains securely stored on the user’s device and never leaves it.
• The public key is sent to and stored by the service.
• To log in, the service sends a challenge to the user's device.
• The user verifies their identity on the device (e.g., via biometric scan).
• The device uses the private key to sign the challenge and sends the signed response back to the service.
• The service uses the public key to verify the signature and grants access if valid.
• This process eliminates the need to enter or remember passwords, while making phishing and credential theft nearly impossible.

Passkeys can be synced across devices using secure cloud services, allowing seamless use on multiple devices. They protect users from phishing because they work only with the registered websites or apps, preventing authentication on fraudulent sites. In summary, passkeys offer a more secure, user- friendly, and phishing-resistant alternative to passwords by leveraging cryptographic keys and biometric or device-based verification.