simnet@ssc-vax.UUCP (Mark R Poulson) (06/01/90)
Someone inquired about protecting a device by running a fiber w/signal through the device -- you'd have to cut the fiber to take the device. It IS possible to tap into a fiber cable. By bending it sharply, some light can escape out of the cable (if you scrape off the insulation). This could conceivably be received by a black box and reinjected into the cable at some other point. This would allow the "security" fiber to be cut. How easy this is to do I don't know. I've never seen devices to do this, but they may exist. It is certainly more difficult than a copper wire though. Around here, any fiber carrying classified data that is not encrypted must be run through a pressurized metal conduit. If the pressure disappears (as it would if you cut into it to get to the fiber) alarms go off. Perhaps this would be a solution for you if you use some flexible tubing and a pressure switch. Mark