Yes, but the initial keys are exchanged in the clear. Hash that against
the IMEI for the working key and you can monitor the GSM phone. The
phone sends its IMEI as part of the login sequence.
(CDMA shares a few similarities (no, they are not the same) with GSM,
but the frames are much larger.)

There are several manuals for GSM service monitors floating about the
net and they each address this in detail. The trick is you have to snag
the key exchange when the phone logs into the network on power up, and
that can only be done if you're on the control channel of the local site
the phone initially powers up in.

If there's one thing we should all be able to agree on, it is for all
intents and purposes, your digital phone is not likely to be listened to
by any hobbiest, it's a far too expensive proposition.

B.





bla wrote:
New Cellular/Cellphones is/are digital & encrypted.

CDMA
UMTS
2G 3G
GSM

For example GSM :

The voice is first digitized using a vocoder and a GSM-codec
then it is encrypted using a special encryption-protocol
that protocol is called A5/1 A5/2 ...etc
After that it is put in 1 of 8 timeslots (TDMA)
after that it is transmitted on a RF-carrier.

hhhuuuhuuuh ...........not finished yet : )

...after that the RF-carrier could be
"frequency-hopping" but this is not everywhere implemented

It depends on the network-operator if and wich crypto is used,
worlwide there are just a few countries without it...

Here's a Yahoo-group wich discusses:


http://groups.yahoo.com/group/gsm-scanner


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GSM-scanners , GSM-interception , GSM-monitoring
GSM-detectors , GSM-encryption , GSM-jammers
GSM-cryptophones , GSM-bugs , GSM-spyphones
GSM-Security , IMSI-catcher , SMS-tricks
GSM-tracking+locating , SIM-Cloning , Bluetooth-tricks
Cellphones , WiFi-phones , CDMA , iDEN , DCS , UMTS , DECT
Satphones , Iridium , Thuraya , Globalstar , Teledesic , Inmarsat

Sales or advertising of illegal equipment is not allowed !

We don't allow or encourage any unlawful behaviour !

This group is moderated wich means that it may take a while
before your postings appear.

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There's a few lists about if and where encryption on GSM is used
and how to find that out using your own phone (monitor-mode)
...etc...etc.