You need to know the algorithm, then it is possible - if they hand you out the key. Without key I see no chance.

Ralph.

From: Tetrapol-kit [mailto:tetrapol-kit-bounces@brmlab.cz] On Behalf Of Helio Machado
Sent: Wednesday, March 16, 2016 10:15 AM
To: Jan Hrach; tetrapol-kit@brmlab.cz
Subject: Re: [Tetrapol-kit] RP-CELP decoder doesn't seem to work

Thanks! Sorry if I bothered you without need.

Is there any chance of implementing decryption?

El mié., 16 mar. 2016 a las 1:14, Jan Hrach (<jenda@yakumo.hrach.eu>) escribió:

As you can see, there is KEY_TYPE=4 KEY_INDEX=5, so your network uses encryption. We are not able to decode it.

The original hardware codec decodes it this way: http://nat.brmlab.cz:8064/tpol/xgm1wspuj5.d/frames.ogg. It is encrypted, so no chance anything hearable will result.

> Only a last question: How can I send the json files to the online decoder?
You run

cat *.json|grep '"type": "VOICE"'| grep -oE '"value": "[0-9a-f]{30}"'| cut -d \" -f 4 | blhexbit | sed -re "s/(.)(.)(.)(.) (.)(.)(.)(.) /\8\7\6\5\4\3\2\1/g" | sed -re "s/^([01]{20})/\1_/g">voice.bits

and then paste the voice.bits file (or part of it as it is huge - sane is about 1500 lines a time) to http://nat.brmlab.cz:8064/

That is exactly what I did to get the above .ogg. However there is no point in it unless you see some traffic with KEY_TYPE=0 KEY_INDEX=0 or KEY_TYPE=15 KEY_INDEX=0, as you will get only encrypted gibberish.


On 15.3.2016 23:49, Helio Machado wrote:
> In the attached zip, I also give the wav files that are the result of using rp-celp python program.
>
> Please listen them and say me if this is the expected output.
>
> Feel free to use the attached captures to make the codec work.
>
> If you request it, I can capture GB of data for you ;-)
>
> Best regards.
>
> El mar., 15 mar. 2016 a las 23:38, Helio Machado (<crushedice2000@gmail.com <mailto:crushedice2000@gmail.com>>) escribió:
>
>     I've found this. I don't know if you've read this yet. Seems interesting.
>
>     http://wenku.baidu.com/view/5692b134ee06eff9aef80752.html
>     http://www.baidu.com/p/line__up?from=wenku
>
>     Seems like tetrapol specs...
>
>     El mar., 15 mar. 2016 a las 22:36, Helio Machado (<crushedice2000@gmail.com <mailto:crushedice2000@gmail.com>>) escribió:
>
>         Ok. Only a last question: How can I send the json files to the online decoder? Should I convert them to some other format?
>
>         Files: https://www.wetransfer.com/downloads/784210d89a2f8ffe6d049f3f21546de020160315212723/e84d021feaff771ccce7b1165c9d17f220160315212723/3ab6b4
>
>         Thanks for your quick response!
>
>         El mar., 15 mar. 2016 a las 20:04, Jan Hrach (<jenda@yakumo.hrach.eu <mailto:jenda@yakumo.hrach.eu>>) escribió:
>
>             https://brmlab.cz/project/sdr/tetrapol/audio
>
>             (yes, you can send them to me via mail too)
>
>             On 15.3.2016 17:36, Helio Machado wrote:
>             > To what site should I upload these json files? Can I upload these files as attachment?
>             >
>             > El mar., 15 mar. 2016 15:59, Jan Hrach <jenda@yakumo.hrach.eu <mailto:jenda@yakumo.hrach.eu> <mailto:jenda@yakumo.hrach.eu <mailto:jenda@yakumo.hrach.eu>>> escribió:
>             >
>             >     Send us session ID (the random string in URL) or these frames.
>             >
>             >     On 15.3.2016 09:29, Helio Machado wrote:
>             >     > Hi! I'm testing the latest tetrapol-kit with a TETRAPOL signal (formerly known as SIRDEE here in Spain). I capture well, and decode to JSON, but when I use the rp-celp codec to extract audio, I only get weird sounds.
>             >     >
>             >     > I don't know if I could send you a sample.
>             >     >
>             >     > crushedice2000 +=|at|=+ thatmailofgoogle . com
>             >     >
>             >     > Thanks in advance.
>             >     >
>             >     > Helio.
>             >     > --
>             >     > Un saludo.
>             >     >     Helio.
>             >     >
>             >     >
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>             >     >
>             >
>             >     --
>             >     Jan Hrach | http://jenda.hrach.eu/
>             >     GPG CD98 5440 4372 0C6D 164D A24D F019 2F8E 6527 282E
>             >
>             > --
>             > Un saludo.
>             >     Helio.
>
>
>             --
>             Jan Hrach | http://jenda.hrach.eu/
>             GPG CD98 5440 4372 0C6D 164D A24D F019 2F8E 6527 282E
>
>         --
>         Un saludo.
>             Helio.
>
>     --
>     Un saludo.
>         Helio.
>
> --
> Un saludo.
>     Helio.


--
Jan Hrach | http://jenda.hrach.eu/
GPG CD98 5440 4372 0C6D 164D A24D F019 2F8E 6527 282E

--

Un saludo.

    Helio.