[135] in cryptography@c2.net mail archive
Re: PCS Encryption?
daemon@ATHENA.MIT.EDU (Andrew Meredith)
Mon Feb 3 14:25:55 1997
Date: Mon, 03 Feb 1997 17:58:26 +0000
From: Andrew Meredith <meredith@ecid.cig.mot.com>
To: Greg Rose <ggr@Qualcomm.com>, cryptography@c2.net
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
--
___________________________________________________________________
Andrew Meredith
Senior Systems Engineer Tel: +44(0) 1793 565377
Network Engineering Tools Grp Fax: +44(0) 1793 565161
GSM Products Division Page: +44(0) 839 421153
Motorola SMTP: meredith@ecid.cig.mot.com
16, Euroway, Blagrove X400: QSWI016@email.mot.com
Swindon, SN5 8YQ, UK SMS: 44860608008@sms.telco.mot.com
___________________________________________________________________
