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15th December 2015, 08:11 AM #1
Decryption key for encrypted RDS-TMC
Hope its ok I open a new thread on this topic. I've learnt a bit more about TMC, and discovered that an encrypted signal may be locking people out not only in Australia, but other countries also.
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My situation is I own a 2013 Mazda CX5 that has a TomTom NB1 built into the dash. The NB1 includes a RDS/TMC receiver and the TomTom navcore (10.854) is able to use the traffic data received.
So I was scratching my head as to why I had a car with TMC hardware and software, in a city that has a TMC broadcast service - why it was not working. People in other countries like the UK and US were driving the exact same car and using TMC traffic! Well with some digging, and help from a few people, it has become clear that many TMC signals are in fact encrypted, and the car or GPS manufactures are required to purchase a license in order to incorporate the decryption key into the navcore in order to use the traffic data.
This is the case in Australia with SUNA, and most other countries. Unfortunately for me, either Mazda or TomTom have not paid for the license, and therefore my TMC capable GPS, whilst able to tune into the SUNA traffic channel, does not have the appropriate decryption key to use the SUNA traffic data.
So, the question becomes - where exactly is the decryption key implemented into the navcore - and can perhaps the decryption key be extracted from another navcore that includes the necessary code.
Whilst no current TomToms seem to have valid licenses with SUNA, there were a number of old devices that did have lifetime subscription (and therefore the suna decryption key included in the navcore.
Those devices are:
XXL 540, XL 340, One 140, 730 Traffic, XL Traffic and Go 720 Traffic
Perhaps if I can work out where the decryption key is, i can extract it from the old navcore - add it to mine and unlock TMC traffic!
In navcore 9, allot of things point to the mctx.dat file. But there is also the GNS folder, and the files in the maps folder - tmccodes.dat and traffic.dat. Issue I'm facing is mctx.dat and GNS folder are not part of navcore 10.854.
Its so frustrating. I actually quite like the TomTom - but end up using Google Maps on my phone most the time - as a GPS that routes you straight into traffic is useless! Interestingly, google maps uses that same traffic data SUNA broadcasts (Intelematics) I could make a request to MAZDA - but its unlikely they will add SUNA support as they have already moved away from TomTom and are using Navteq maps in the 2015 CX5 model.
Here is another article I stumbled across related to TMC decryption.
poshea Reviewed by poshea on . Decryption key for encrypted RDS-TMC Hope its ok I open a new thread on this topic. I've learnt a bit more about TMC, and discovered that an encrypted signal may be locking people out not only in Australia, but other countries also. My situation is I own a 2013 Mazda CX5 that has a TomTom NB1 built into the dash. The NB1 includes a RDS/TMC receiver and the TomTom navcore (10.854) is able to use the traffic data received. So I was scratching my head as to why I had a car with TMC hardware and software, in a city that has a Rating: 5
21st December 2015, 06:32 PM #2
QUESTION: I've noticed that some navcores when downloaded come with a whole bunch of files and folders (similar to what I have on my SDCARD... And others only have the ttsystem file. I understand, in my case anyway, that when the ttsystem is on my SDCARD root - when I start my car/tomtom the new navcore is installed ( I guess to some internal storage)
It's a bit blurry for me how much of the navcore is contained within the ttsystem file... And how much resides on the SDCARD.
Is there a way to extract the data within the ttsystem file? And then recompile it?
I guess in my case I'm wondering if the missing decryption key is missing from my SDCARD, OR from within the Navcore ttsystem file itself. (Note: In my case, the ttsystem file is automatically removed from the SDCARD after its installed.)
21st December 2015, 07:17 PM #3AdministratorJoin Date : Dec 2011Location : UKPosts : 4,218Thanks: 10,728
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A navcore (or application) is a lot more than just a ttsystem file (the actual file that needs to be patched to enable the navcore itself to read cracked/activated maps)
If you download a new navcore direct from TT (as you would if you were just updating the navcore via TTHome etc) then you wouldn't get all the files & folders, just those that had been updated whereas any SE-type navcore round here is normally the whole thing (incl a pre-patched ttsystem file) needing only a map folder adding to it to run (once activated)Please do not just post "thanks" but use the "thanks" button bottom/right or the reputation star "*" bottom/leftS i m p l e s
21st December 2015, 11:48 PM #4TomTom Master
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I think he' talking about built-in TT - such as MAZDA - these indeed contains only huge ttsystem file, which appears to be kinda linux iso.
22nd December 2015, 04:11 AM #5
if I agree with Rusigor
Mazda mate speaks, all packaged within NavCore this TTSYSTEM in this case could have another name, has nothing to do with the old navcores which consisted of several folders and files with one TTSYSTEM, PNDNavigator within or extracted to the root
22nd December 2015, 01:29 PM #6
Thanks guys! I am actually running simbas mazda patched navcore (Mazda NB1 10.854)
or Original unpatched file here:
As you'll see, the navcore contains only the following files:
Other navcores included more files and folders plus a much smaller ttsystem file.
9.540.2-2040-CAB-navcore-LE : ttsystem 4.5mb
9.510.1-2039.CAB-navcore-GO : ttsystem 8.2mb
8.351.go530-go730-go930.CAB-navcore-GO : ttsytem 8.1mb
Also interesting that the PNDNavigator DOES NOT reside on my Mazda NB1 sdcard. Is it contained within the ttsystem archive for the Mazda NB1?
This could explain why placing the mctx.dat and /GNS folder on my sdcard is having no effect. Perhaps its not looking for those files on the sdcard, but on its internal memory - as was installed from within the ttsystem file? Just a theory :P
I've tried a few methods of extracting a file structure from within the ttsystem file. I renamed to ttsystem.iso or ttsystem.img or ttsystem.cab I'm on mac, so tried disk mounter and also an app called Keka that is meant to be able extract .iso, .exe .cab etc It fails to extract anything.
Any thoughts or suggestions?
22nd December 2015, 09:30 PM #7
previous navcores forget, this is different.
Here is the content of TTSYSTEM, extract the contents contentfs.gz vera of folders and files .
Here there is PNDNavigator in the / bin this is the equivalent ttn PNDNavigator
23rd December 2015, 07:50 AM #8
Thanks simba!!! I found the mctx.dat in 10.854
As you said, inside 10_854_ttsytem-extraido there is a contentsfs.gz
I extracted this and got a contentfs file. I was able to then extract this with mac os archive utility. This gave me a contentfs folder. Inside this folder, along other files and folders, was the mctx.dat file. I believe this to be the most likely file to contain decryption keys for encrypted RSD/TMC stations. I compared to mctx.dat from 8.351.go530-go730-go930.CAB-navcore-GO. This was reported as the last navcore that worked with SUNA TMC in Australia. The files are both 4kb but there is definitely a few lines of additional code inside the older 8.351 mctx.dat file.
So what I need to do is replace the 10.854 mctx.dat file (located in ttsystem/contentsfs.gz/contentsfs/mctx.dat) with the mctx dat from 8.351.go530-go730-go930.CAB-navcore-GO
Then I would need to recompile/archive into a single ttsystem file to install the altered navcore on the Mazda. (in the same way I installed simbas patched navcore) If the old mctx.dat file is transferred to the car as part of the navcore, and this file does contain needed decryption key for SUNA traffic - then we may have success!!
#simba : can you please message me what tools I need to use to extract and then re-archive ttsystem.
if the mctx.dat alone doesn't work, i found a few other TMC related files within the ttsystem that could be relevant. like:
Could be others, but that's what i found at first glance. Obviously trying to pinpoint specifically whats related to tmc encryption/decryption. Allot of these files may be just general TMC integration. Thats why I think its worth just trying changing mctx.dat only first.
23rd December 2015, 04:47 PM #9
l do not have a tool is manual one by one.
but it is one thing to unpack and one pack is many files with different permits.
i am going to be abroad for several days and memory of you
by not having my computer with more information.
if to conquer new ttsystem any member of the board can help you.
25th December 2015, 03:49 PM #10
Thanks simba. I figured Linux. Had a play with binwalk... But not much luck on OS X. Not much experience in terminal. Anyway, have a good Christmas to you and everyone. I can see how it will be a tricky task to unpack and repack ttsystem. But if anyone can do it... you can!! Let me know if your able to take a look at it when you get back from your holiday. Many thanks!