Itunes Backup Password Never Set

[IATSE]

I just recently got a new phone and traded in my old one for the new one. Backup my phone through itunes and encrypted was selected but it never prompted me for a pw. Got the new phone back to the house and of course it was asking for a pw that was never set. Just wondering if anyone knew of where itunes might pull a password from. I've been trying to crack this for over a week now. Used rockyou word list, made my own word list and a couple variations, tried brute force with numbers only out to 6 places, I've been using best64 rules on my word list as well.

 Hashcat has been pretty amazing but I feel like I'm just stabbing in the dark at this point. So I figured I would ask here if anyone knew where itunes gets that password info if you don't specify one. Thanks.