[mdlug] Curious - Phone Tapping Tech

[Robert Adkins II]

> 
> On Thu, Jun 21, 2012 at 1:53 PM, Aaron Kulkis 
> <akulkis00 at gmail.com> wrote:
> > Michael Mol wrote:
> >> On Thu, Jun 21, 2012 at 11:21 AM, Robert Adkins II 
> <radkins at impelind.com> wrote:
> >>> I am curious to know if phone tapping technology has "caught up" 
> >>> with Holywood. In terms of being able to take a band and wrap it 
> >>> around a bundle of phone lines and call that a tapped line.
> >>>
> >>> I'm curious, because everything that I know regarding this 
> >>> technology requires that each individual line be physically 
> >>> tapped/connected to in order to obtain anything.
> >>>
> >>> I'm talking about Plain Old Telephone Service. Nothing 
> fancy like IP 
> >>> based or similar.
> >>
> >> Oh, sure. When I was a kid, I could hear my parents' telephone 
> >> conversations by picking up the second phone line; it's called 
> >> crosstalk, and it's a form of accidental inductive coupling.
> >>
> >> They've probably been making the accidental intentional since WWII.
> >>
> >
> > That's one pair PARALLEL to the other pair, and is an entirely 
> > different scenario (wrapped AROUND the bundle, and 
> therefor, a plane 
> > perpendicular to the pair carrying the signal to be detected).
> 
> I was answering the question of whether snooping is plausible 
> to begin with, not whether or not a specific technique is plausible.
> 
> Yes, if your conductor is parallel to the magnetic field, 
> direct inductive pickup won't work.
> 
> >
> >
> >> Doing the same thing with a *bundle* of cables would be a bit 
> >> tricker...but you could probably do a decent job filtering 
> crap out 
> >> with enough signal processing. Filtering out DSL frequencies to 
> >> start, then finding any frequency band groups that stop 
> and start (as 
> >> would happen with a human vocal conversation), and locking 
> in on those.
> >> Eventually, you'd need to get a human involved to separate out 
> >> overlapping conversations.
> >>
> >> Though, no, I don't expect you could wrap around a bundle 
> of cables 
> >> and hone in on a specific copper pair.
> >
> > You couldn't detect a signal even if it was only 1 copper pair.
> > Don't believe me?  Try it.
> 
> Hall effect sensors would do it easily, in the single-pair 
> case. And if that isn't enough, you could use the signal 
> propagation detection and lock-on technique I wrote about 
> last week to do it. I came up with that in response to the 
> 'thermal noise' encryption thing that was making the rounds 
> last week. It requires three measuring points, and then 
> applies triangulation in a time+distance space to figure out 
> where a signal is coming from and when, and uses that to lock 
> on for pass/block filtering purposes. The hardest part is 
> timecode synchronization between the three measuring points.
> 
> --
> :wq
> _______________________________________________


None of which, I presume, is fundamentally easy to accomplish, setup,
configure and operate for the layman.

-Rob