Apple has updated its security for a number of apps and now Apple two step verification is used on FaceTime and iMessage.
Apple two step verifications is now available for FaceTime and iMessage on the iPhone, iPad and also the Mac.
This security feature has been available for Apple’s iCloud since 2013, although iMessage and FaceTime did not have the two step verification, which meant that they could have been more vulnerable than other apps.
Now if you log into iMessage of FaceTime on a different device or different Mac you will need to complete the two step authentication.
When you sign into a new device you will need to enter your password and then a 4 digit verification code that is sent directly to one of your already registered devices, you can find out full information on how to set the verification up over at Apple.
Source The Guardian, Techmeme