I'm not sure what the problem you are having is here. Transport can be secure with TLS. Content can be secured with smime or even archaic and ancient pgp. Leaky

I'm not sure what the problem you are having is here. Transport can be secure with TLS. Content can be secured with smime or even archaic and ancient pgp. Leaky metadata is a problem with every protocol that can be routed. Oh, and email is one of the few things on the internet that universally works...