Satellite eavesdropping of 802.11b traffic

Perry E. Metzger perry at
Thu May 27 21:19:17 EDT 2004

"R. A. Hettinga" <rah at> writes:
> At 12:35 PM -0400 5/27/04, John Kelsey wrote:
>>Does anyone know whether the low-power nature of wireless LANs protects
>>them from eavesdropping by satellite?
> It seems to me that you'd need a pretty big dish in orbit to get that kind
> of resolution.
> The Keyholes(?) are for microwaves, right?

Dunno if it would work in orbit,, but you can get surprising results
right here on earth using phased arrays.

Vivato is selling very long range phased array equipment as long
range/high quality 802.11 basestations, but you could do precisely the
same trick to eavesdrop instead of to communicate. With enough
computing power, one device could listen in on every 802.11
communication in a very large radius.

I don't know how practical it would be to set up some sort of large
scale phased array in orbit -- I suspect the answer is "not practical
at all" -- but the principle could apply there, too.


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