I was hoping that the paid version of CloudBerry Explorer could allow me to upload and automatically encrypt files to S3. Unfortunately, it seems that while there is a choice of encryption algorithms, no additional processing can be done on the crypt key that is used. In our use of S3, we use one of the standard algorithms, but do some additional manipulation of the key.

Here's my request for an enhancement to the settings available in your upload rule definition to allow for a hook so that a custom step can be run before the key is used. Maybe something as simple as an entry for an endpoint that could process the key or a way to specify running a local script which could do the same.