Can I log in using a passkey instead of a password?

Yes, if said passkey supports the PRF (Pseudo-Random Function) feature, you can use it to log in without needing to enter your password.

When you log in with a passkey that supports PRF, the passkey itself securely generates the necessary cryptographic keys on your device. This allows your browser to derive the required encryption keys to access your account data without ever transmitting your password.

At the time of writing, passkey providers that seem to support PRF are:

• iCloud Keychain (Apple devices)
• Google Password Manager (Android and Chrome)
• Windows Hello (Windows devices)

Most hardware security keys (like YubiKeys) also support PRF, allowing for passwordless logins.

If your passkey does not support PRF, you will still need to enter your password to log in, as the password is required to decrypt your account's encryption keys.