Okay, let's suppose that the NSA/NIST/Mykotronix Registered Key system becomes standard and I'm able to buy such a system from my local radio shack. Every phone comes with a built in chip and the government has the key to every phone call. I go and buy a phone and dutifully register the key. What's to prevent me from swapping phones with a friend or buying a used phone at a garage sale? Whooa. The secret registered keys just became unsynchronized. When the government comes to listen in, they only receive gobbledly-gook because the secret key registered under my name isn't the right one. That leads me to conjecture that: 1) The system isn't that secure. There are just two master keys that work for all the phones in the country. The part about registering your keys is just bogus. or 2) The system is vulnerable to simple phone swapping attacks like this. Criminals will quickly figure this out and go to town. In either case, I think we need to look at this a bit deeper. -Peter Wayner