MD380 privacy - how good is it?

[HudsonScannerGuy]

The privacy on the MD380's, how good is it? Is it inversion? Or scrambling, I am trying to find cheaper radios for a school environment and they want SECURE radios apparently.. Any insight would be helpful. Or if there are any other CCR's with Privacy, let me know! Thanks.

 

[jonwienke]

Enhanced Privacy is actual encryption, not inversion scrambling. The NSA can probably crack it, but it's not something the local skript kiddie can decode.

Basic Privacy is trivially crackable.

 

[RayAir]

Enhanced Privacy is OK.

Check your key on another radio without encryption though, because I had a few keys that didn't "encrypt" too good.

They were 32 digital hexadecimal keys and a few just made the voice sound choppy and robotic.

So, I'd say it's generally good enough. But it's far from AES, by a light year or two.

 

[HudsonScannerGuy]

Ah. Okay then.. thanks!

 

[RayAir]

If you plan on using these radios for a school that wants something cheap and private I would strap the voice privacy and probably just use basic privacy.

I don't use the MD-380 anymore, but I had problems with the radios dropping out of EP mode if it received an unencrypted signal, or a basic privacy coded signal. The radio would then no longer function in EP mode until you rewrote it using CPS.

If in BP mode, I never had it do that.
If you use a BP key, for example- 'D8F5', it should offer reasonable privacy.

I don't see that much of a gain by using the TYT 128 bit EP mode. It uses no IV, and from what I've read the key stream is actually 49 bits.

Also keep in mind, it will process any signal it receives if on the same frequency and color code.
If it received a clear signal from some outside user and you have privacy activated on your radio, it will play garbled audio.

 

[jonwienke]

I don't see that much of a gain by using the TYT 128 bit EP mode. It uses no IV, and from what I've read the key stream is actually 49 bits.

Also keep in mind, it will process any signal it receives if on the same frequency and color code.
If it received a clear signal from some outside user and you have privacy activated on your radio, it will play garbled audio.

The latest TYT firmware does use an IV in EP mode. It also appears to fix the problem with dropping out of EP mode. I did some testing, and wasn't able to disable EP by sending unencrypted transmission to the radio.

You can eliminate receiving garbled audio from third parties by using a random 7-digit numbers for your encrypted talkgroup IDs. The odds of someone else using the same talkgroup ID is pretty slim.

 

[RayAir]

The latest TYT firmware does use an IV in EP mode. It also appears to fix the problem with dropping out of EP mode. I did some testing, and wasn't able to disable EP by sending unencrypted transmission to the radio.

You can eliminate receiving garbled audio from third parties by using a random 7-digit numbers for your encrypted talkgroup IDs. The odds of someone else using the same talkgroup ID is pretty slim.

Good to hear they fixed it. I'll have to try this out.

I sent you a PM.

 

[RayAir]

Ugh...

Tested firmware D003.020 and the 128-bit EP is the same as before:
- No privacy indicator
- No MI
- Processes received clear voice through scrambler

But, it doesn't drop out of EP mode anymore.
So that's good.

 

[jonwienke]

When you say "no privacy indicator" are you referring to the flag in the data, or the radio display? Because there is an icon on the display (a checkered shield) when EP is active.

Not sure what you mean by "MI".

I wouldn't consider "processes clear voice through scrambler" to be a bug or an issue. If a channel is supposed to be secured, that forces anyone who has their privacy settings configured incorrectly, or not configured at all, to fix their settings before they can communicate on the channel. Otherwise you'll enable some lazy or malicious individual to talk on the channel in the clear without others realizing they are unauthorized.

 

[Forts]

Those are the more technical aspects of DMR packets. A PI (privacy indicator) header is part of a packet that indicates enhanced privacy or AES is in use (basic privacy doesn't use this as it's not really a form of encryption). The MI is another packet (Message Indicator) which carries data like the KeyID and the Algorithm ID. The absence of these packets indicates that TYT is doing something weird with their encryption and certainly aren't conforming to any of the DMR standards.

 

[jonwienke]

So the voice data is being encrypted, but none of the usual headers and flags indicating the use of encryption are being broadcast. You have to know the KeyID, the associated key value, and the algorithm to properly decode the data.

 

[Forts]

Well you need all that regardless... It basically means they are using some bizarre format that doesn't adhere to DMR standards, so who knows how secure it is, etc.