> But then that raises the question of why you need crypto if everything is already encrypted and verified via TLS. Depends where the TLS path terminates and w

> But then that raises the question of why you need crypto if everything is already encrypted and verified via TLS. Depends where the TLS path terminates and what your threat model is. If I send a message via a service (an email via gmail.com for instance) the message is only protected by TLS as far as that provider. If the content itself is encrypted as well as the transport (and that provider does not know the keys) then the message is still protected at that point. This could be important for code sending data via an API proxy of some sort. Also remember that the user of the browser might not have control over what certificates are trusted for HTTPS purposes. If they are operating in an environment where a local CA certificate is installed and that is used by a transparent proxy to enable them to inspect otherwise secure streams, the application protecting the content as well as the transport may protect against that (though you'll be wanting to use PKI here - otherwise you have a key distribution problem).