Currently to restore your data you need to provide your private key:

> As you prepare a restore, you must type in your private passphrase into the restore server.

Seems like a pretty fundamental architecture fail here.

Later the site goes on to acknowledge this:

> We actually want to improve this to provide a password encrypted ZIP file for download, and then the FINAL improvement is to actually allow you to download the private encryption key, download the encrypted files, and provide the pass phrase in the privacy of your computer. We hope to add this functionality in the future.