Read Freenet documentation. They encrypt everything, yet they use very efficient deduplication. I really like Freenet's design. Encryption key is based on the payload, so if you don't know what he payload is, you can't decrypt the packet. Of course decryption keys can be delivered using different encrypted tree of keys, which is used when you deliver download link.
For that reason, when ever I'm sharing anything I usually encrypt files with my recipients public keys before sending those out. Just to make sure that data is really private and keys are known only to my selected peers. In some cases when I want to make stuff even more private, I encrypt data separately with each recipients public key, so you can't even see list of public key ID's which are required to decrypt the data.
I also have 'secure work station' which is hardened and not connected to internet. That's the workstation I use to decrypt, handle and encrypt data. Only encrypted and signed data is allowed to come and go to that workstation.
For that reason, when ever I'm sharing anything I usually encrypt files with my recipients public keys before sending those out. Just to make sure that data is really private and keys are known only to my selected peers. In some cases when I want to make stuff even more private, I encrypt data separately with each recipients public key, so you can't even see list of public key ID's which are required to decrypt the data.
I also have 'secure work station' which is hardened and not connected to internet. That's the workstation I use to decrypt, handle and encrypt data. Only encrypted and signed data is allowed to come and go to that workstation.