Remote Data Backup - Users Guide
File EncryptionFor maximum security we recommend that you encrypt your data before transferring them to our servers. A great product for encrypting your data is TrueCrypt (http://www.truecrypt.org).
TrueCrypt is a widely used, open source disk encryption software that allows you to create a large, single, encrypted file that can be mounted as a drive letter and used like any other filesystem.
TrueCrypt software runs on Windows, Mac OSX, and Unix, is free, open source software and is supported both by a large community of developers and end users
When the filesystem is unmounted, the encrypted filesystem reverts back to its single, encrypted file.
The internal structure of truecrypt disk images make it possible to efficiently rsync them to a remote location. This means that after the initial (complete) upload of your TrueCrypt disk image, subsequent uploads will efficiently transfer only the changes that have been made to the encrypted filesystem since its last upload.