Application Hash exchange between client and server

Hi Sir/Madam,It would be a nice feature if we can exchange hashes between server and browser. a client as a browser would send clients' browser hash signature and the server would send it's application hash signature. This way, as a client, I would insure that I am communicating to the right version of application I intend (in case if this application is open source) and as a server, the server would insure that it's communicating to the right clients' browser as intended(that for example, could protect and view my data).
Thank you,