Yes, you can already add your own encryption on top of the push system. What I was proposing is that it is standardised and doesn't require any extra code from

Yes, you can already add your own encryption on top of the push system. What I was proposing is that it is standardised and doesn't require any extra code from the application developer. So when I want to push a message out to one of my users, the push software I am using will handle encrypting it, and the push software on the users device will handle decrypting it. They will both be aware of the encryption keys involved because they will have negotiated them during the initial direct connection and will have them stored.