Comment by defaultcompany

Interesting! I can picture how the clients could calculate a hash prior to encryption and that would let the server know those files have the same contents once decrypted but how would that let them save on disk space? They still can’t see the contents of the file itself even if they know it’s the same so how could they deduplicate the storage? If they drop either one they are just left with a single encrypted version using only one clients key which they can’t serve up to anyone else.