A passkey is a modern way to sign in without typing a normal password. Instead of remembering a secret word, your phone, computer, or security key proves that you are the right person by using cryptography. You might unlock the passkey with your fingerprint, face scan, screen lock, or device PIN.
Passkeys work with two connected keys. One key stays privately on your device, and the other key is stored by the website or app. When you sign in, the website sends a challenge. Your device answers it with the private key, but the private key itself is not sent over the internet. This makes passkeys much harder to steal through phishing than ordinary passwords.
For users, a passkey usually feels simple. You visit a site, choose the passkey option, and approve the sign-in on your device. There is no password to reuse across sites and no long code to remember. Some passkeys can sync through an account provider, while others may stay on one device or a hardware security key.
Passkeys are closely related to WebAuthn, which is a web standard that helps browsers and websites support this kind of secure sign-in. They also fit well with Zero Trust Security, because identity needs to be verified carefully before access is granted.
The main benefit of a passkey is that it reduces common password problems. People cannot easily choose weak passkeys, reuse them on unsafe sites, or type them into a fake login page. That does not make every account automatically perfect, but it removes one of the biggest weaknesses in everyday online security.