[Sorry, I don't have the attribution for the fist quote. The remainder of the post was authored by a friend of mine who retired from decades in military SIGINT. He allowed me to forward it to the list.]
don't emit enough radiation for Bad Guys to read it. CRTs are well known as emitters of easily decoded signal, but people have occasionally suggested on this list that laptop LCD screens are much quieter. I now have a data point on this one, and basically, it ain't so.
Look - if it uses electricity; if there is an oscillator anywhere innit; if there is a ground loop in the circuit design, if there are make/break contacts anywhere - It will radiate, and the amount it radiates is directly proportional to the basic power source ... And circuit board traces are getting so damned close that engineers I know/knew were worried about friggin' arc-over at 3 volts. By now, may be even closer and voltage worries lower... So we have a problem. The only computer I know of that is (at this date) leak-proof is the biological one 'twixt one's ears. And soon, maybe not even that. Those who laugh at the paranoiacs who wear aluminum helmets and wear shoes with a static strap to the sidewalk may be laughing out the other side of their moufs too soon... As for any government directives requiring companies to make computers leak, I know of none, but CAVEAT: I've been retired from source info since '91, and most of my friends/fellow engrs who occasionally got together for a few brewskis and BS sessions over in Mt. View have either gone to better jobs (more $$$), transferred back east, or inconsiderately died. So, who knows? And of course, the ability to detect this RF/RFI/EMI leakage from your information processor is similarly dependent on the sensitivity of the equipment you're using for detection. I've seen absolute magic performed using a Wullenweber antenna, and that is NOT state-of-the-art equipment any more (ca. 1965-70), even tho the DoD keeps throwing money at it in upgrades (affectionately called 'the elephant's cage' by those who worked with it). If you really need to keep your information processing "private", then you can either isolate yourself inside a double-shielded room of solid copper; power everything with batteries; have no wires leading out of that room; make damned sure the door has the nice secure wiping strips to complete the shield when you close it -- or move your information processor into the middle of a whole bunch of the same or worse RF/RFI/EMI emitters, and just _maybe_ your data will get lost or become inaccessible because of the overload of the detection equipment by much larger interference fields. Or use paper, pencil, and one-time pads and burn everything that's done "in the clear" and really scrunch the ashes into dust. [Again, I am not the author of the above post.] -- Lucky Green <mailto:shamrock@netcom.com> PGP encrypted mail preferred Make your mark in the history of mathematics. Use the spare cycles of your PC/PPC/UNIX box to help find a new prime. http://ourworld.compuserve.com/homepages/justforfun/prime.htm