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From: simnet@ssc-vax.UUCP (Mark R Poulson)
Newsgroups: sci.electronics
Subject: Re: Fiber optic security
Summary: not perfect
Message-ID: <1475@ssc-bee.ssc-vax.UUCP>
Date: 31 May 90 18:30:13 GMT
Organization: Boeing Aerospace & Electronics, Seattle WA
Lines: 19
References:


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