Digital Spread Spectrum = DSS
OK, one more time for those of you who have just tuned in. Digital
signal decoding of D.S.S.s is
possible, but not feasible. Allow
me to elaborate:
Let's say we wanted to monitor
Joe on D.S.S. A. Nevermind the legality, that's been done to
death - we all know better, but
this is just a hypothetical example. No harm, no foul. Now then...
D.S.S. A is a XYZ co digital encrypted
D.S.S.. Great. All we need to do is get a copy of the
XYZ D.S.S. companies' digital
protocol for it's D.S.S. system. (As soon as someone figures out where
all
these companies hand out such
literature, please let me know, huh?) Once we can see the protocol, we
can hopefully
understand it enough to reverse
it and sequence all the 0's and 1's into the correct order and send them
to a
specialized circuit that takes
the binary stream and converts it to voice. You'll probably need the schematic
to the
D.S.S. set-up as well for that.
Now the tricky part - the encryption.
Once we can decode a valid frame sequence (all digital
radios need one to let it know
where the data starts and stops) then we just try every possible combination
of
those bits until we find a match.
IF (and that's a big IF, as it assumes no extra 0's and 1's were added
in the
encryption sequence just to mess
with our minds) that happened then maybe after an hour/day/week/month/etc.
of
processor time,you might hear
Joe saying "Hello..."
Great! We've got it! We listen
in on Joe for the rest of the conversation (That probably took
place days ago) and hear leave.
Then he starts again and... aw , the code changes when he does that...
So
the program (you have to write
it yourself - I guess I should've mentioned that first) has to
start hunting for a new code all
over again. This repeats ad nauseum until we get sick of monitoring Joe.
Then we see Sally across the street
talking on D.S.S. set-up B. Ahh, this might be good, so
we run our new program/circuit
on Sally's D.S.S. frequency. but nothing happens - our program can't
decipher it at all! A closer look
reveals her D.S.S. set-up is an ABC co D.S.S.. Uh, oh..
They use a different protocol
over at ABC co for their D.S.S. set-up... So we get to start from scratch
again.
(The examples below are not the
real values OK guys? I don't think I need to look these up to
make a point...)This is just narrow
band 900MHz . DSS adds a new twist as it takes a radio transmission and
scatters it across a large chunk
of the allocated band. So you could find a piece of Sally or Joe's D.S.S.
transmission on more than a dozen
different frequencies. It would take a Rich Wellsian collection of scanners
to cover all the possible frequencies
all at once. And your PC has to make sense of all this.
So to answer the question, the
SOFTWARE angle is not going to happen. It just isn't.
Now, the hardware angle - modifying
an existing unit to make it a D.S.S. "scanner" - is much
more feasible.Much more. But that's
a whole other rant unto itself. ;-)
I hope that helps explain it..
-Phil Smalley Please note: ScannerWay does not, nor does it's provider, nor does this document endorse in any way the monitoring of private wireless transmissions. It is clearly just an explanation of how hard it would be to accomplish. Therefore this document actually deters people from attempting to decode a dss type signal.
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