h > > Doesn't that make it vulnerable (detectable) to Tempest attacks? h > > Harka rw> No. rw> Transmitting light via fiber doesn't emit EM. Light is electromagnetic :-) rw> Anyway, the original post, as I recall, was about keeping sensitive data rw> on a second hard drive, connected via (very thin, therefore harder to rw> notice) fiber. Tempest monitoring was not a factor. rw> -r.w. I assume that if you've got a fiber hanging from your PC, and thugs come in to steal/confiscate/forfeitize your PC, that they're bright enough to notice it and maybe to follow it. Thugs who want your information will follow it to find information; thugs who just want to resell your hardware will follow it to find more hardware. I had initially assumed that the mention of fiber optics was in the context of "Infrared transmitter on the PC, fiber optic sticking out of the wall to receive the IR and transmit it to a hidden detector." or something silly like that. If you want to hide a small PC in your attic/wall/etc and use the newer faster IR stuff for clandestine backups, and have a Real Operating System so you can run it in the background (since your disk drive is presumably much faster than IR), I suppose you could do that. The main use of TEMPEST here is to detect backup systems hidden in the attic that they hadn't noticed. Hiding it in your stereo system doesn't protect it from honest thieves, who might also want to resell your stereo, and info thieves have been known to seize anything even resembling computer equipment, such as Mozart CDs. You could also hide the computer in your kitchen cabinets like one Famous Cypherpunk, but you'd have to use a thinner bundle of cables than he does to connect the monitors and keyboards :-) # Thanks; Bill # Bill Stewart +1-415-442-2215 stewarts@ix.netcom.com # http://www.idiom.com/~wcs # Confuse Authority!