Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!att!cbnews!military
From: denbeste@BBN.COM (Steven Den Beste)
Newsgroups: sci.military
Subject: "Identify-Friend-or-Foe" questions
Message-ID: <12566@cbnews.ATT.COM>
Date: 23 Dec 89 06:05:09 GMT
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From: Steven Den Beste <denbeste@BBN.COM>


I would appreciate it if someone would post a description of how the "IFF"
system works. Every way I can think of that it could work provides a way for an
enemy to abuse the system. For instance, in a jet with such
a system:

1. IFF broadcasts its signature continuously. In that case an enemy missile
	could home in on the broadcast.

2. IFF answers with its signature whenever someone else broadcasts a query.
	A missile could be equipped with a query-broadcaster and then
	home in on the answer.

3. A missile refuses to hit an enemy target because it identifies itself as
	friendly, even though it isn't.

#1 and #2 are particularly a problem because Electronic Counter Measures can't
be used to prevent this without nullifying the IFF system entirely. (That is,
if a friendly system can use IFF to abort an attack, an enemy system can
equally use it to complete an attack.)

There were rumors after the Falklands war that HMS Sheffield didn't try to
stop the incoming Exocet because IFF had identified it as friendly (French).
This was denied, and then the whole subject was hushed up. I still wonder about
this.


Steven C. Den Beste     denbeste@spdcc.com
                        harvard!spdcc!denbeste

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