This is very thought-provoking. One observation: I don't completely understand all this yet, but it appears that what distinguishes the system from one that is

This is very thought-provoking. One observation: I don't completely understand all this yet, but it appears that what distinguishes the system from one that is entirely trusting of client-side JS code, is the fact that the e-mail provider signs user's key. That means that we must be able to get the e-mail provider's public key somehow. There is supposed to be no central authority, so we must get it directly from the e-mail provider. Your link includes this line: > 4. Public key(s) for gmail.com are attained from a well-known location on their servers (specifics TBD). This service is absolutely necessary to get BrowserID working, but they haven't figured out the specifics yet. I think they need to get beyond that "TBD" pretty darned quick.