I'll get to that. Unless you have a very high degree of assurance that the individual presenting the credentials is entitled to do that, what you end up doing is issuing a very secure document obtained under false pretences.
In terms of RFID, there are efforts in several countries to embed these in various forms of identity documents—driver's licences, health cards, etc., the notion being that it will make the particular transaction that the card is designed for quicker, more efficient. For example, you don't need to swipe the passport. You just need to wave it by the reader. The problem with that is that until fairly recently that communication was not protected in any way. So anybody who had access to the radio frequency spectrum could read that information.