Apple recently added two-step verification to Apple IDs. This optional feature helps thwart hackers from using your Apple ID. This mechanism requires you to enter a four digit code after entering your usual password. The code is delivered to your iOS devices or your cell phone. In most cases, a hacker won’t have access to these devices. In the information security world, double authentication is typically called two-factor authentication. The first factor, your password, is something you know. The second factor is something you have, your iOS device or cell phone. As part of the registration process for two-step verification, Apple also gives you a recovery key to print out. The recovery key can be used to manage your Apple ID if you lose your registered devices.
Whenever you manage your Apple ID at appleid.apple.com or make purchase for the first time with your ID on a device, you’ll be required to enter the four digit code delivered to your device.
If you forget your password, you’ll need the recovery key and one of your registered devices to reset it.