Backups, what compression format?
 

I was wondering what could be using the space in my backups so I transferred the files to my PC to take a look.

They appear to be .zip files, but I can't find anything to open them with. I tried WinRAR and Windows 7 itself, but the say the compression format is unknown.

I password protect them, so is that causing some issue?

Re: Backups, what compression format?
 

Yes, the protection is the issue. It still labels them as ZIP files but they're actually encrypted (but not using standard ZIP security).

Re: Backups, what compression format?
 

Damn, I thought as much. I'll do another backup without a password and try that.

So is there anything PC based that can decrypt them, obviously knowing the password? I don't want to hack the files.

Re: Backups, what compression format?
 

download and install winrar and 7zip then try to open the files

only encrypts them if you have a password. they are probably tar files

Re: Backups, what compression format?
 

I've no idea what encryption they're using, so I don't know.

Re: Backups, what compression format?
 

Unfortunately the backup app isn't open source, so we can't check their encryption algorithm. Closed-source encryption isn't a very good idea in general.

Re: Backups, what compression format?
 

The software using a published algorithm may be closed or open source matters not as long as the implementation of the algo is correct (granted with closed source you cannot check it, but few have the expertise to check crypto implementations anyway...).

Probably the encryption algo is AES, but at which point exactly the backup is encrypted is a question (for example is there some sort of header on the archive file telling that it's an encrypted archive or is it all just "randon noise" and the backup restore program will just suppose that file of extension X with no headers is encrypted backup archive).