Know RAS key for a protected MotoTRBO system - Can I now listen with an SDR?

[SpectralContent]

I have access to the RAS key for a particular DMR Cap+ system that I would like to monitor using an SDR software. I am currently familiar with DSD+ and SDRTrunk programs. Is there any way to input the RAS key to be able to effectively decode and listen to this system in any of these two programs? Is there another SDR program that allows for the option to put in a RAS key if it is known? I'm sure this is a very rare instance, but wanted to see if it was possible!

 

[GTR8000]

RAS only impedes scanning with a MOTOTRBO radio, not scanners or software. If the system uses encryption, that's a different story (and no, there is nowhere in the software to enter a BP/EP key even if you had it)

 

[SpectralContent]

Thanks. Yea it's encryption, not RAS only. I never really thought until now how RAS doesn't imped anything outside of mototrbo radios. I have all the keys for encryption. Sounds like I'll have to program up a trbo radio for any hopes of listening.

 

[Ubbe]

RAS jumbles up the checksums for the audio frames and not having the correct RAS key will have the decoder think that the signal has too many errors to be able to be decoded. To be able to listen without a RAS key you have to ignore the checksum and then also the forward error correction will not work that will then increase the error rate. So you will need a higher signal strength for that system compared to one where the checksums are intact.

If you try and listen with a Whistler scanner you will have to set the flag for that conventional channel to handle RAS, but Whistler didn't included that for trunked system or in the firmware for TRX-E. They closed development before that could be fixed. If you try and listen with a real DMR radio to a RAS coded signal without the correct RAS key or a non MotoTrbo radio it won't give any sound at all as it thinks the signal are too bad as the checksums doesn't match in the data frames.

/Ubbe

 

[slicerwizard]

RAS jumbles up the checksums for the audio frames

No, it doesn't. RAS affects link control data checksums.

 

[RRR]

. If you try and listen with a real DMR radio to a RAS coded signal without the correct RAS key or a non MotoTrbo radio it won't give any sound at all as it thinks the signal are too bad as the checksums doesn't match in the data frames.
/Ubbe

The XPR 5XXX Kenwood Series radios with DMR at current FW don't seem to have an issue monitoring RAS enabled Mototrbo systems.

"RAS" proper is a Motorola encoding, it is not DMR standard.

If another manufacturer decides to add an equivalent of RAS to their firmware, that's up to them.

 

[CanesFan95]

But will those Kenwoods trunktrack Capacity Plus?

 

[noamlivne]

I have access to the RAS key for a particular DMR Cap+ system that I would like to monitor using an SDR software. I am currently familiar with DSD+ and SDRTrunk programs. Is there any way to input the RAS key to be able to effectively decode and listen to this system in any of these two programs? Is there another SDR program that allows for the option to put in a RAS key if it is known? I'm sure this is a very rare instance, but wanted to see if it was possible!

Hi,
Check out the videos of this guy, for example,

He offers his software for A LOT of $$$$. I certainly would not even think of buying it.
I have no experience or affiliation to it, but understand that it can work.

Probably it only gives you the audio and not the Talkgroups and Channels and User IDs.

Maybe in the far future someone will have the know-how and prepare a free for all program that offers this special feature (especially if you know already the key).

 

[natedawg1604]

But will those Kenwoods trunktrack Capacity Plus?

NO, from my understanding no Kenwood radio is capable of monitoring ANY type of trunked system without the system key, basically the software won't let you program anything trunking related unless you're a system user.

 

[Forts]

Capacity Plus is a Motorola proprietary format, there aren't any other commercial radios that I'm aware of that will work with it.

 

[slicerwizard]

Hi,
Check out the videos of this guy, for example,
He offers his software for A LOT of $$$$. I certainly would not even think of buying it.
I have no experience or affiliation to it, but understand that it can work.

Probably it only gives you the audio and not the Talkgroups and Channels and User IDs.

Maybe in the far future someone will have the know-how and prepare a free for all program that offers this special feature (especially if you know already the key).

BP doesn't touch link control data, so why wouldn't that software show group and user IDs?

Basic Privacy is extremely weak ghetto encryption and has nothing to do with RAS, so what's your point?

 

[noamlivne]

BP doesn't touch link control data, so why wouldn't that software show group and user IDs?

Basic Privacy is extremely weak ghetto encryption and has nothing to do with RAS, so what's your point?

I am no expert so I have no knowledge about what goes on behind the scenes.

But we are receiving a new system here that Dsdplus and SDRTrunk do not show Talk Groups, Channels, UIDs, nothing, and no audio. It also does not show that there is an encryption. Nothing is shown. But it is known that this system is very active.
Sometimes the word RAS appears in Dsdplus with this system.

In addition, some people sent that guy that owns the above mentioned software raw data of this "cloaked" network, and he delivered to them a few seconds of clear audio as a proof that his program works. He returned that file with the words "Hytera 10ch BP decrypted".
So I thought it is a system protected with RAS (and encrypted with BP). The RAS part being something similar to this "Hytera “Over-the-Air” Encryption":

https://hytera-europe.com/news/security-and-encryption

Regarding showing the TG, channels and UIDs by this software, I simply did not see them shown in the videos he posted. I only hear the audio.

Anyway, perhaps I am mixing up the terms. Sorry about that.
Thank you very much for the explanation.

 

[AM909]

...

https://hytera-europe.com/news/security-and-encryption

...

Not sure how it relates, but wading through the BS, there is this bit, specifically about Hytera's OTA encryption:

... only rarely is the actual signaling used to set up the call protected. Hytera’s over-the-air encryption solution is designed to prevent this vulnerability. Over-the-air encryption encrypts the signaling on the air interface meaning all of the information is encrypted from call setup through to reception at the transmitter. ...

 

[GTR8000]

Link Layer Encryption. All signaling is secure from start to finish, not just the voice traffic. If the system is the type that uses a dedicated control channel, that is encrypted as well, meaning that you can't even observe the activity on the system. Oh and it's coming to P25 soon, by the way...already being worked into the TIA-102 standards.

 

[a417]

Maybe in the far future someone will have the know-how and prepare a free for all program that offers this special feature (especially if you know already the key).

Hah.

 

[CanesFan95]

I wish for a software that lets you put in the BP key so you can try all 255 keys and figure out the key.

 

[GTR8000]

I wish for a software that lets you put in the BP key so you can try all 255 keys and figure out the key.

Cool.

 

[KevinC]

Since we're wishing for things I wish for an official Red Ryder, carbine action, 200-shot, range model air rifle, with a compass in the stock and this thing that tells time.

 

[a417]

Since we're wishing for things I wish for an official Red Ryder, carbine action, 200-shot, range model air rifle, with a compass in the stock and this thing that tells time.

...you'll shoot your eye out.

 

[Forts]

Link Layer Encryption. All signaling is secure from start to finish, not just the voice traffic. If the system is the type that uses a dedicated control channel, that is encrypted as well, meaning that you can't even observe the activity on the system. Oh and it's coming to P25 soon, by the way...already being worked into the TIA-102 standards.

+1 for this. There is a Hytera system near me that is fully 'cloaked' if you will. As mentioned they have to ability to fully obfuscate all over the air activity.