What end-to-end encryption should look like
Tangential (and noob) question: Could there be an encryption+compression scheme where:<p>1. Sender sends an encrypted stream at K bps.<p>2. Server takes the encrypted stream and compresses it, without decrypting anything. It then sends encrypted+compressed stream at J bps (J<K) to end recipient.<p>3. The end recipient decrypts the compressed stream using a key provided by the original sender, not the server.<p>This with reasonably secure encryption and reasonably size-efficient codecs, obviously. So the step 2 would add compression additional to the compression of the original codec.<p>Is this mathematically possible?