All keys are held by DataShell - you can however use a third party encryption tool to encrypt the files before uploading them/backing them up.
However if you do use a third party encryption tool, please note that you will be limited to functionality in the web portal such as having to download the file, decrypt before the file can be viewed.
Hope that answers your question.
I would most definitely be interested in a trial, if it weren't for this. Sorry, but a novice data storage / backup service should most definitely include
client side encryption.
Related to this, a technical question: for large binary files, do you sync the complete file, or is there some smart partial differencing system (e.g. using hashes of 1MB blocks or whatever) to only upload the changed parts of a file?
Because I'd feel the urge to put a TrueCrypt container inside the DataShell folder, and backup that (to make sure I have the data security of client side encryption). But if I make a few small changes within a TrueCrypt volume of 1 GB, will it upload the entire volume, or just the changed parts?