Nokia voice encryption device project - GSM-Forum

MegaADY · 11-07-2003, 00:33

Hi there guys ! Yesterday, I had a project ideea. I thought about a gsm encryption device. The

A5 algorythm is safe enough for a lame hacker who want to tap a conversation over the air, but

the guys from the phone company can listern to you quite easy. So , why not building a few

crypting devices, and double encoding the communications between a few phones ...
I thought about two methods of doing this.
1. The encoding device can be inside the phone, inserted between the A/D D/A converter and

the main processor, where the digital signal is A5 encrypted.I studied Nokia 3310 schematic,

and found out quite interesting things.
COBBA asIC provides an interface between the baseband and the RF circuitry . COBBA performs

A/D conversion of the analog signal comming from the microphone, and fr the transmit path

COBBA performs D/A conversion.COBBA is connected with the main processor MAD2WD1 with two

serial interfaces, one for transferring rx/tx signals between MAD2WD1 and COBBA, and one for

transferringcodec Rx/Tx samples.I thought about cutting the PCM samples lines ( rx and Tx )

and inserting a microcontroller programmed to crypt theese samples. As you can see in the

pictures, on theese lines there are four fumpers ... so I think that can access these lines,

somewhere on the surface of PCB, without desoldering MAD2 or COBBA. If someone knows where

theese jumpers are located on the PCB please feel free to mail me.

2.The encoding device can be done outside the phone, conected at Rx/Tx on the external

accessory connector, and the call will be in fact a data type call. But this in far more

complicated.I have an ideea doing this, but I would prefer the first way.

If someone is interested in this project and can help somehow, please feel free topost here .
Thank you

MegaADY · 11-07-2003, 00:36

mad2

Luciano · 11-07-2003, 15:49

what do you think if you use external device connected like Hands Free device... this way you can use few phone models...

unlteam · 11-10-2003, 13:48

external devices already available

MegaADY · 11-10-2003, 15:09

Do you have some schematics ?

crusher · 11-18-2003, 22:08

yes he has... but he won't share for free what he stole

no hard feelings, Anatoly

11-10-2003, 13:48	#4 (permalink)
unlteam Freak Poster Join Date: Aug 2002 Posts: 286 Member: 14875 Status: Offline Thanks Meter: 1	external devices already available external devices already available

11-10-2003, 15:09	#5 (permalink)
MegaADY Junior Member Join Date: May 2003 Location: Ashgard Posts: 12 Member: 29497 Status: Offline Thanks Meter: 2	Where can I find such a thing ? Do you have some schematics ?

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Using old Nokia LCD in your projects	Dave.W	GSM Programming & Reverse Engineering	3	02-17-2009 19:42
Nokia voice encryption device project	MegaADY	Nokia Hardware & Hardware Repair	3	11-09-2003 14:16
voice encryption device project	MegaADY	Hardware Repair by brands	3	11-07-2003 21:00

11-07-2003, 15:49	#3 (permalink)
Luciano Freak Poster Join Date: Aug 2001 Location: RO Posts: 479 Member: 5992 Status: Offline Thanks Meter: 1	what do you think if you use external device connected like Hands Free device... this way you can use few phone models...

11-18-2003, 22:08	#6 (permalink)
crusher No Life Poster Join Date: Dec 2001 Location: [winscard.SCardTransmit] Posts: 1,835 Member: 8023 Status: Offline Thanks Meter: 13	yes he has... but he won't share for free what he stole no hard feelings, Anatoly