https://9to5mac.com/2022/06/07/passkeys-passwordless-sign-in-ios-16/
..Apple revealed that iOS 16 and macOS 13 finally enable passwordless sign-in with “passkeys.”
In fact, iOS 15 and macOS 12 are already compatible with FIDO Standard. However, the previous implementation requires the user to log into each app or website on each device before enabling a passwordless sign-in method. Now with Apple’s latest software, true passwordless sign-in has become a reality.
How passkeys work in iOS
For users, sign-in with a passkey will work pretty much the same as a sign-in using iCloud Keychain and Face ID or Touch ID. You just choose a credential, authenticate with biometrics, and that’s it. However, while iCloud Keychain basically auto-fills your username and password into regular text fields, a passkey goes far beyond that.The system generates a unique key that can only be accessed with user authentication via Face ID or Touch ID. This prevents malicious websites from trying to steal your passwords since passkeys are securely stored in the iCloud Keychain and are not visible to the user….but what about other platforms? Since passkeys are based on the FIDO Standard, which is also being implemented on Android and Windows, there’s a way to sign-in to on a device that is not yours.
The other device generates a QR Code that can be read by your iPhone or iPad. iOS uses Face ID or Touch ID to confirm that it’s you who’s trying to sign in before confirming or denying the request to the app or website running on the other device. ..