NSA tapping undersea fibers?

[John Denker]

I was talking with some colleagues who had read the WSJ article

>http://interactive.wsj.com/articles/SB990563785151302644.htm
>
>http://www.zdnet.com/zdnn/stories/news/0,4586,2764372,00.html for

... and who were wondering as follows:  Given that They know how to tap a 
fiber in the lab, how hard it would be for a submarine such as the USS 
Jimmy Carter to apply a tap while working 3000 meters down in the ocean.

Well, it ain't gonna happen by sending any such sub down to 3000 meters.

It is highly unusual for a full-sized sub to go below 500 meters.  US subs, 
which are believed to be not as tough as the Russian ones, are limited to 
something more like 300 meters.
   http://www.fas.org/nuke/guide/russia/slbm/941.htm
   http://www.fas.org/nuke/guide/usa/slbm/ssbn-726.htm

One might have guessed that subs could zoom down 1000 meters about as 
easily as airplanes can zoom up 1000 meters -- but that's not the case.


According to the WSJ article, near shore (at depths of less than 1000 
feet), the cable is buried in a trench, which would add an extra layer of 
nuisance to someone trying to tap it.  Out in the deep ocean, it just lies 
on the seafloor -- but the pressure becomes a big issue.

Here's are some hypothetical scenarios to consider:

First, it should be obvious that They don't need a submarine to tap cables 
that already make landfall in the US, which is the vast majority:
   http://www.telegeography.com/Publications/cmap00.html
... and They can't use a submarine to tap the cables that go from China to 
Russia,
... but I suppose there are things like AfricaONE:
   http://www.africaone.com/english/maps/Africa_ONE_segments_022801.jpg
where underwater tapping might make sense to Them.

Anyway, here's scenario #1:  To tap a deep-sea cable, They keep the 
submarine at a modest depth, perhaps 150 meters or so.  They send down a 
small Remotely Operated Vehicle to grab the cable and lift it up to the 
sub.  They do the work there, and then return the cable to the seafloor.

The cable is certainly strong enough and flexible enough to permit 
this.  (Otherwise, how could it ever have been laid?)

But could the tappers do this without leaving telltale signs?  I don't 
know.  It depends on how closely the tappees are watching.

If I owned a cable, I might want to have an ROV of my own, and use it every 
so often to patrol the cable end-to-end, looking for signs of disturbance.

Another scenario:  Overall it might be easier to tap the cable while it is 
still on the continental shelf, at 100-meter depth or so.  That would 
require Them to dig it out of its trench and re-bury it, but thereafter it 
would be hard for others to notice Their handiwork.

===========

Related issue:

Suppose They install a tap.  What then?  What are They going to use for 
backhaul?!!

   1) One option would be to use some other channel on the same cable to do 
the backhaul.
    1.1) This would be "relatively" straightforward if They could lease a 
suitable backhaul channel from the cable operator.  I don't know how this 
could be done without the cable operator knowing exactly what They were up 
to.  And if the cable operator is giving Them that level of consent, there 
are ways of getting the data without bothering with a submarine.
    1.2) Without a leased backhaul channel, I suppose it is possible that 
They could just insert packets into the stream of traffic, on the fly, but 
this would be exceedingly tricky, because of the high speeds and delicate 
timing.
   2) Another option would be to lay a backhaul fiber from the 
tapping-point all the way back to Maryland.  If They did this, somebody 
with an ROV could detect it, whereupon it would be rather embarrassing for 
Them.

Bottom line:  I don't understand how to do the backhaul, and without 
backhaul the whole story doesn't hang together.  Ideas, anyone?




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