full parallel power of device

[rarecoil]

the guesses hashcat is making are assuming that the password used for the backup are ones that exist in rockyou.txt. rockyou.txt contains a lot of very simple passwords, so there is no guarantee that the password is one that exists in rockyou.txt. with slow hash constructs like itunes, you are best off trying to remember some part of the password. knowing even the length of the backup encryption password will tell you whether cracking this is feasible.

i think that is what is important to understand about hashcat. it is not decrypting or recovering anything. it is simply trying to guess the password for you based upon a list of passwords. you can run for 55 days and get nothing.