The data is also encrypted with your own key. I know that's an option with at least one of those Mozy or Backblaze apps but definitely not with Dropbox.
Backblaze encrypts your data with your own key, but you can't restore your data unless you give Backblaze your key. When you restore, step 1 is to enter your key into their web page. Also, if you order a hard drive with your files, the hard drive is shipped with your unencrypted files on it.
