Unmaintained dependency iOSbackup

[gonsoos]

The dependency iOSbackup seems to be unmaintained judging by the open issues and PRs and the lack of commits for three years. Importantly, the project's license isn't fully specified, as its setup.py states "LGPL", but not which version. Lastly, it has no test suite to speak of.

You may want to consider switch to another dependency.

[roaree]

I don't feel the license is that big of a problem. Unfortunately re: maintainability, there is an issue with corrupted files after decryption that I think stems from inaccurate filesizes in backup metadata which iOSBackup (arguably correctly) truncates :(

https://github.com/jsharkey13/iphone_backup_decrypt might be worth exploring as it looks simpler, so I'll keep this open.

[besendorf]

iphone_backup_decrypt has no methods for implementing the extract-key mvt command. We would either need to drop the feature or implement it ourself