Right. Block and stream Ciphers themselves can only protect message content. The leak the message length and any peer metadata during the exchange. A perfect ci

Right. Block and stream Ciphers themselves can only protect message content. The leak the message length and any peer metadata during the exchange. A perfect cipher produces a message that is indistinguishable from randomness, and can encode all possible messages. This is an intrinsic problem, when we want to hide the cipher texts existence, we usually call that steganography which is a different class of problem. Likewise, hiding the communication graph or message length is more akin to mixnets and anonymity networks/routing. It’s three classes of problems, of which encryption is the base layer, but we need more constructions to achieve the other layers.