Apple introduced two-step authentication some while ago, but even months after that happening, it was limited — until today: Apple has rolled out internationally two-step authentication for FaceTime and iMessage as well (via The Guardian).
Users trying to log in to FaceTime or iMessage with their Apple ID and password will be greeted with the following message: “App-specific password required. Your Apple ID is protected with two-step verification. You must generate an app-specific password at appleid.apple.com to sign in.”
If you don’t want to use the service, you can choose later, but hitting “Create” will open the aforementioned Apple ID site, where — after logging in — you will get a prompt to generate the app-specific password. You can name the app for which this password will be used and then hit “Generate.”
The result will be an app key, which you will then paste into the password field to log in to FaceTime, for example.
If you are already using FaceTime on your Mac, you won’t get this prompt: you will need to sign out and then sign in once again to benefit from Apple’s latest attempt to make its services secure.