FYI, even if you use your own key, Mozy only encrypts the contents, not the filenames. That's rather insufficient. A court could subpoena them for a list of your files, establish that particular files exists, and require you to produce them. See http://michaelshadle.com/2007/05/07/mozy-the-backup-client-damn-close-but-still-no-cigar/

Plug: In 2006 I founded https://spideroak.com/ specifically to provide a zero-knowledge approach to online backups. We don't know anything about your data, including your file and foldernames. On the servers we just see sequentially numbered data blocks. It's written in Python and C and we've always supported Linux and OS X (and Windows if that's what you're into.) SpiderOak keeps historical versions of your files and deleted files forever (or until you decide to remove them) and will sync folders for you across several computers. Some reviews are http://www.linuxplanet.com/linuxplanet/reviews/6644/1/ and http://www.maclife.com/article/reviews/online_storage_battle_which_cloud_backup_service_reigns_supreme

And they can't search inside your documents.

Encryption specs are are here: https://spideroak.com/engineering_matters#encryption_specifications

We like to say that trust isn't necessary because we're incapable of betraying our users. It's makes good business sense too. We don't want to spend our time answering subpoenas. :)

To add your own layer of encryption, you can archive container files or whatever you like. No limits. If you a sector based encrypted disk image, SpiderOak will be able to efficiently snapshot it between versions, giving you history and only saving the changes between revisions.

If you want a layer of additional local control, there's a "Keep your own copy" option where SpiderOak will put a copy of every encrypted data block on your own server, so you can manually inspect them if you wish (and have offline/local access for very fast restores.)

FYI, even if you use your own key, Mozy only encrypts the contents, not the filenames. That could be a problem for some people. A court could establish that a particular file exists, and then require you to produce it. See http://michaelshadle.com/2007/05/07/mozy-the-backup-client-damn-close-but-still-no-cigar/ for more info.

There's no reason online can't be secure. Online means it's automatically offsite and that a 3rd party has the time and incentive to be sure it's actually working.

2 years ago I founded https://spideroak.com/ for this exact situation -- wanting a zero-knowledge approach to encryption. We explicitly don't know anything about your data. We just see boring sequentially numbered data blocks on the server. Instead of a EULA, we have a "remember your password" agreement.

You can combine data from unlimited devices and it de-duplicates, and can automatically sync folders for you. Storage is perpetual (unless you explicitly remove things.) FWIW, it's written in Python and we have always supported Linux.