How does the (optional) encryption work? Do I have to supply my own key/password? I.e. can you decrypt the data if forced to?
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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.