Re: [PEN-TEST] How secure is an ISDN line? Fibre Optic TAPs

["Alexander Sarras (SEA)" <Alexander.Sarras () SEA ERICSSON SE>]

> From: Peter Gamache [mailto:peter () LUNO ORG]
> Sent: Tuesday, 24 October, 2000 11:36 PM
> To: PEN-TEST () SECURITYFOCUS COM
> Subject: Re: [PEN-TEST] How secure is an ISDN line? Fibre Optic TAPs
>
>
> "van der Kooij, Hugo" wrote:
>
> > On Tue, 24 Oct 2000, Talisker wrote:
> >
> > I just saw some mentioning of using quantum level signaling to
prevent
> > taps. As at this level you can't inspect a signal without altering
it. So
> > a good CRC check would notice tampering with the transmission.
> Can anyone see a way to get past the nitrogen/pressure sensor defense?

Sure. Since that pressure normally isn't very much above normal, you
could use some sort of glove-box. Might not be very inconspicuous, too.

Concerning quantum optics: Yes it would be quite "easy". But compare the
cost for a new, proprietary transmission protocol, including routers and
switches, and it might just be cheaper to mount a 24/7 guard.

I still believe in walkable conduits, using fiber-cable bundles,
assigning each strand a different channel, and taking that channel down
as soon as there's a even minimum interruption in the connection, or
signal dampening. Using 3 to 4 strands for the same information and
comparing the signals might help a lot. After that it's back to walking
the line again, I'm afraid. Depending on the laws of your country you
could use closed conduits filled with something more or less "nasty".

Good luck
SaS
--
Dr. Alexander Sarras
Ericsson Austria         | Phone: +43 1 811 00 4668
Pottendorferstr. 25
A-1121 Wien
Austria

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