"build a better online identity solution than creaky old HTTP cookies. " Yeah we already have that. It's called HTTPS cookies, supported by all browsers, secure and has negligible costs to implement. HTTPS is our only practical solution. Even if this Unobtainable solution were to be invented today, have zero per user cost to implement, somehow magically be simpler than SSL, be universally accepted, we would still have to wait months if not years for it to supported well enough in every browser and web server. We _have_ the solution, we know it _works_, we know _how_ to use it, all we have to do _is_ use it.