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The following archive was created by hippie-mail 7.98617-22 on Fri Aug 21 1998 - 17:16:06 ADT
Per Kangru (perk@fysik.uu.se)
Thu, 19 Mar 1998 08:30:09 +0100 (UPP)
On Wed, 18 Mar 1998, William H. Geiger III wrote:
> >> a little old and slow but then again no one does any real work on
> >> WinBlows so it's not a problem. :)
>
> >Are you saying that a Standard UPS provides too little isolation?
>
> Yes, yes I am. :)
>
> Standard UPS's do not operate with their batteries "on-line" but in
> standby mode. Because of this you do not get any of the filtering affect
> from the batteries. You can get good "online" UPS's with gel-cell battery
> banks but they cost $$$. Look at some of the companies that service the
> telcom industry providing UPS for switchrooms. Line conditioning on the
> standard UPS's (PC Decsktop grade) is medeocere at best and are designed
> for leveling out power fluctuations not for filtering data leakage.
>
> If Tempest is a serious concern I recomend a dual battery bank so one bank
> can be charging while the other is in use. Physicial disconnects on both
> battery banks between the computer and between outside power grid to
> insure physicial issolation durring operations.
>
As all of us know very well the weakest link in the chain is always the
one that will break. You measures with batteries wont do that much if you
are not in a totaly shielded enviroment. This means for example you CANT
have ANY electric connections form your computer or the room/shield you
are in to the outside. You must have your electrical generator inside the
shield or by some kind of mechanical device.
You CANT have any equipment that is connected to the outside in a
electrical sense. Ofcourse you must be sitting in a farady cage also.
This is about what it takes to be quite hard to eavesdrop on.
There is a few diffrent techniques to shield your computer without all
this fancy stuff but it is very hard to filter out all the outgoing
signals.
Any one that got any evidence that TEMPEST monitoring has been used by
either individuals or organisations to eavsdrop?
/Per
The following archive was created by hippie-mail 7.98617-22 on Fri Aug 21 1998 - 17:16:06 ADT