On 25 Mar 99, at 8:18, Jim Meagher wrote:

> IN ADDITION, consider that the internet is a PACKET SWITCHING network
> -- which means that your message is chopped up into many pieces
> (packets - packages) that are each sent (in many/most cases) by a
> different route.  All the individual pieces do not "flow" down the
> "highway" one behind the other in a nice logical progression.

  While ordering of packets is not guaranteed -- plaintext credit card
numbers are likely to be safe *IF* they are split amongst several
packets -- the topology of the net is not really an amorphous mesh.
It's more like a tree with a trunk (backbone) and smaller and smaller
branches and finally leaves.  A sniffer located at the base of one
"branch" could see all traffic between nodes (leaves or branches) on
that branch, and locations on any *other* branch.  [Traffic between two
small branches that are on the same big branch may not need to pass the
sniffer....]
  The point is only that despite the Internet's packet-switched
protocols, there are points in between you and any server where your
messages may be intercepted and read.  [There is a building a few miles
from me, over at NASA's Ames Research Center; it is estimated that as
much as a third of all Internet traffic flows through that building on
its way from place to place.  It's rumoured, by those who believe in
conspiracy theories, to be one of the six or so strategic locations
where the NSA monitors Internet traffic....]

  Ordinarily, it's convenient to think of the Internet as a "cloud"
where you drop things in at one point and they reappear later at
another.  But that convenient metaphor is just a little too simplified
for an accurate security assessment.


David G

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