I lost password to my iPhone 4 backup! Actually, I would not recall ever setting one. Now however, I’ve a new phone and can’t restore it through the backup, as there it prompts me for any password I don’t have! I tried all the ones I’ve for my iPhone and pretty much every other one of which I can think, all to no avail. I want the information inside the backup. But I am unable to get to it. I’ve already tried the keychain option to no avail. Does anyone have suggestions? I have a MacBook Pro running Mac 10.6.7 and iTunes 10.2.2. The iPhone is usually an apple iPhone 4.
I got voices from people around me:
1. It is not your fault – I was never asked to encrypt the backup – it is doing it on its own.
2. You, like me, may never have been asked for a password to encrypt your backups
3. Your current backup options may currently say you don’t have encryption enabled – mine don’t, and adding one in doesn’t work
4. The issue is that at some point in the distant past, either my iPod or iTunes has asked me for a password – at it may have felt like it wasn’t going to be important, as I keep all my passwords of any importance in a file, but obviously didn’t put this one in.
5. The way to unlock iPhone 4 backup password is to get the pro iPhone Backup Password Unlocker software as follows:
A. Download iPhone Backup Unlocker and set it up.
B. Open WordPad and make data saved with the extension .txt. therein file jot down as much from the passwords you have ever used, (tap return in between each) any keywords and phrases you may use in passwords, to offer the software program a chance, try shortening some to 8 letters united the of mails says as mine was 8 letters anyway so can’t prove/disprove this but worthwhile, just invest as many feasible that your head may have produce to give it a possibility.
C. Then in the software lick for the green plus button to include folders, and direct it to your document, add the alternative maximum mutations, swap the order from the files when using the green arrows to ensure the dictionary file runs second ( as it takes a number of years).
D. Then run it, whether it gets passed your file towards dictionary file, I would suggest you stop it, get back on your text file separately and beat in as numerous other possible permutations of passwords you might have used, save it and check out again.
For more detailed steps on how to unlock password to iPhone 4, you can refer to video on “Unlock iPhohe Backup Password”!

Source: http://www.iphone-recovery.net/unlock-iphone-4-backup-password.html