What if I can't get double certification when I return to the factory and can't get into the Iphone?

1. Take out the mobile phone card and put it in the second mobile phone to accept SMS. You can fill in the verification code after receiving the verification message.

2. If there is no second mobile phone and the local phone number can be used normally, you can use the voice verification code. Wait for the voice message and fill in the verification code.

3. If you still can't receive it, you will have a second chance to enter the verification code after entering the system. At this point, you can receive the verification code information.

The difference between two-step authentication and double authentication

1. Close

"Two-step authentication" can only be enabled on the management page of Apple ID.

"Double Authentication" can only be opened on the iCloud account management page of iOS 9.3 or OSX10.11.4.

2. Equipment registration method

When two-step verification is enabled, the system will ask you to send the verification code to each iOS device enabled with Find My iPhone, so that the corresponding device can be set as a trusted device and used to receive the verification code.

When Double Authentication is enabled, the system will automatically set all devices registered in iCloud as "trusted devices".

Both methods require manual verification of trusted phone numbers.

Step 3 get the key back

"Two-step authentication" will generate a series of "recovery keys" as a backup means to restore account access rights.

Two-factor authentication does not generate any recovery keys.

4. Verification process

When logging in Apple ID on an untrusted device or browser, both authentication methods require an additional verification code to confirm the identity.

After entering the account password, Two-Step Authentication will ask you to select a trusted device or a trusted phone number to receive a series of four-digit verification codes.

"Double Authentication" will automatically send login reminders to all trusted devices, or you can manually choose to use your mobile phone number to receive the verification code. Different from the "two-step verification", the login reminder not only contains the verification code, but also shows the approximate geographical location of the account login, and the length of the verification code has also expanded from four to six.

Users can choose whether to allow login attempts on any device. If "Allow" is selected, the system will automatically display a six-digit verification code, otherwise, the login will be directly refused. After selecting on one device, the login reminders on other devices will automatically disappear.

5. Device receiving verification code

Two-step verification can only send verification code to iOS devices.

"Double Authentication" can send verification codes to iOS devices and Macs.

6. Use offline

When all trusted devices and trusted phone numbers are offline, two-step authentication will not be available, which may cause trouble for your login.

And "double authentication" can generate verification code offline on "trusted devices", which greatly simplifies the user experience.

If you want to log in to Apple ID on devices before iOS 9 and OS X El Capitan, you need to manually generate a verification code, and enter the account password in the password field of the old device, followed by the generated six-digit verification code.

7. Change of safety information

When Two-Step Authentication is enabled, you can only modify the security information in the Apple ID, including Trusted Devices.

"Double Authentication" allows you to modify the account management page directly on the device side.

8. Handling after forgetting the password

"Two-step authentication" requires you to have any two of account password, recovery key and a "trusted device" that can receive verification code to access Apple ID. Once you lose any two of these three things, you will lose access to your Apple ID forever.

Two-factor authentication has no recovery key. When you forget your password, you can't use trusted devices and trusted phone numbers, you can also use account recovery and submit relevant information to Apple for review in an attempt to re-access your account. Apple technical support has no right to interfere with the process of "account recovery", which has put an end to "internal ghosts" to some extent.