signing is a more expensive operation by like factor of 4 or more than deriving a decryption secret and making a cipher block stream

not wanting to see messages that have been encrypted to you is quite retarded, i mean, i don't even know how to express how retarded it is to not want to spend the cheapest amount of crypto compute on seeing what people send you

signing stuff, that's a different issue because implicitly you are also sending that out, there should be a clear delineation between actions that are secret and actions that become public or at least move to private across the connection

i admonish you guys to do some more study on cryptography and signals intelligence, please