I fixed this problem. I never set my iphone backups to be encrypted. But after ios7 upgrade, iTunes kept prompting me for a password to restore my iphone backup (argggg!).
I tried my Apple ID password: No.
I tried my MacOS "user" password: No.
Tried my iphone's unlock passcode: No.
Then I found a video on youtube that gave me a big hint. Video is called "After Updating iPhone to iOS 7 How to Restore iTunes Backup Password".
This told me there is a SEPARATE "iTunes backup password" that iTunes must have prompted me to set a long time ago.
So I tried a bunch of passwords I have used in the past, and after about 5 tries, I typed the matching password and the restore started and completed.
The video claims there's a program to recover the "itunes backup pw", but I didn't need to go there (since I eventually got a match).