Date: Fri, 16 Apr 1993 14:54 CDT From: Peter Wayner 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. Knowing nothing except what I've read on the net today, I suppose that while scrambling the phone conversation the chip inserts in the data stream some ID (perhaps once per second) to tell the govt. which chip is doing the scrambling. This would allow multiple trapdoor keys (as claimed) and also there would be no need for phone users to register. The chip might also insert the number of the phone originating and/or receiving the call, though presumably the wiretappers would already know this. -- Peter Meyer