There are 3 workable ways to unlock the unknown backup password:
Method 1: Find Lost Password to iTunes Backup by Setting a New One
This is a method I read from Apple Support Community and it is proved by many people. This method, to be exact, doesn't find you iTunes backup password but use the new password you set to replace the old one.
Here is how to:
On the summary page on iTunes, go down to the backup section
Check "Encrypt iPhone backup" part and entered a new password.
Go to restore and when iTunes asks for the password, simply put in the password you just set it as and it works.
Method 2: Find Forgotten iTunes Backup Password with Keychain Access on Mac
Mac users have an option to recover iTunes backup password with the Keychain utility but this is not guaranteed to work for everyone because it depends on the usage of Keychain in Mac OS X.
Here is how to:
- Open Keychain Access, found in /Applications/Utilities/
- Use the Search box in the upper right corner and type "iphone backup"
- Double click the result, assuming something is found in Keychain
- Check the box next to "Show password" and enter the Mac administrator password to find password for keychain file iTunes backup.
Method 3: Find Your iTunes Password with Tenorshare iTunes Backup Unlocker
- Download and install iPhone Backup Unlocker on your computer and run it after the installation.
- Click on "Add" on the main interface to import your password protected backup file.
- Select an attack type to unlock iPhone password backup files. (Brute-force Attack, Brute-force with Mask Attack and Directory Attack.)
- Click on "Start" to find your forgotten iTunes backup password. After several minutes, your password will be listed in the File Opening Password Box.