PCS Encryption?
Andrew Meredith
meredith at ecid.cig.mot.com
Mon Feb 3 12:11:41 PST 1997
Greg Rose wrote:
>
> The three different digital standards in North America are TDMA,
> CDMA, and GSM (in NY and DC only AFAIK).
GSM is also a Time Division Multiple Access (TDMA) system. In it's
original form it uses specrum around 900 MHz, which I believe not to be
available in the US. Shame really, I can roam with my GSM phone over
pretty much the rest of the planet ... except the US.
Anyway, there are two higher frequency derivatives, PCS1800 & PCS1900,
which have been deployed in the US. I'm not involved directly in the US
market so I'm not sure where. I assume however that these are the
systems to which Greg refers.
> Newer analog phones use at least some of this, but I don't know much
> about them. I'll ignore GSM.
^^^^^^^^^^^^^^^
Aww shame ;)
> The conclusion is that neither way of doing it is truly
> cryptographically strong, but both are a lot better than
> listening to Princess Di call Newt "Squidgy" on a Radio Shack
> scanner.
GSM uses the A5 algorithm which *is* cryptographically strong, but is
unfortunately considered to be top secret stuff. If, however, you were
to pick up a copy of "Applied Cryptography, 2nd Edition" by Bruce
Schneier you may find something of interest.
I hope that you'll work out from my .sig why I can't say much more.
Hope this helps
Andy M
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Andrew Meredith
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