Radioddity GD-77 Privacy Compatibility with other radios

[EI9BAB]

The standard firmware of the GD-77 allows for Basic Privacy or None and you can select/program your own key with 8 Hex Characters. As far as I know most forms of BP just use plain XOR operations in the background. Obviously other radios use different pre-programmed keys and have longer or shorter key lengths and probably different algorithms. However, some of these are 4 Hex Characters and just use simple XOR.

What I was wondering was is if you set up the GD-77 with a 2 x 4 character key (e.g. F016F016) and then there happened to be another manufacturer who used F016 as one of their Basic Privacy keys, would you be able to communicate between the different radios? There are probably some radios that this might work for and some that it would not, probably depending on how simple/complex the algorithm is. I am only thinking about Basic Privacy and obviously Enhanced Privacy would not work as the algorithm is more complex.

I am not trying to decrypt anyone else's private transmissions. I am just wondering about the mixing of different radios and if they could theoretically work together. Does anyone have any ideas what might be compatible with Radioditty radios like the GD-77 in theory with such an approach please? (For example, Motorola, Tytera.) Thanks.

 

[a417]

I would not count on any compatibility between vendors, especially CCR vendors.

 

[alcahuete]

The GD77 is not compatible with any other radios as far as encryption is concerned.

 

[dazey77]

As others say. Generally my understanding is that all basic encryption tends to be not compatible cross manufacturers (e.g. hytera + moto can't interop with basic encryption) but where manufacturers offer an add on AES encryption scheme then this may/should be. I believe that hytera aes can work with moto AES (but I have never tried it)

 

[Forts]

Yes, Hytera ehanced privacy and AES work with Motorola (and likely other vendors). However as mentioned most of the cheaper radios just do their own thing when it comes to encryption. It's often very poorly implemented and doesn't work with anyone else.

 

[jaspence]

The number of posts indicate you are fairly new here. If you are in the US, you should know that encryption is illegal on ham bands and listening to legally encrypted signals is a federal offense.

 

[EI9BAB]

Thanks for all the replies. I appreciate the polite warnings - I am not based in the US but I am a licensed Radio Ham. We don't do encryption on the ham bands here either but I also use radios commercially. I have been careful in these forums and I understand the sensitivity about talking about Encryption but there was clarification that it is not forbidden - it just needs to be in the right place. I had hoped this was the right place for this specific question but I don't want to cause any friction!

I would point out that if I knew/guessed a BP key then I could just use that kind of radio to listen to another station if I really wanted (or there are affordable programs available to buy which do this.) So, I don't really need to hack a different radio to achieve the same thing. I am just interested in the compatibility between radios as I plan to purchase more in future and would like to understand how they could inter-operate.

So, I do understand that if you take Motorola radio out of the box and switch on Basic Privacy then it will not be able to communicate with a different manufacturer. My uninformed opinion is that reason is that Key 1 on a Motorola might be "010F" and key 1 on a Hytera might be "03EE" and there is no overlap of these keys between manufacturers. (I made up those keys in case anyone's worried! ) As far as I have read, the basic process is to XOR those keys against the bytes in the voice frames and that there was no complex algorithm behind that. So I just wondered if theoretically you could use the same Hex value in another BP radio (as you can program that on a GD-77 but not necessarily on a Motorola rig) and then they might work together.

It seems the answer is assumed to be "Never" but I'm still not sure why. I suppose there must be a lot more to the process than I had gathered. If anyone has any more detail or has actually tried this then I would still be interested to learn more. Thanks again.

 

[AM909]

If I were a manufacturer, unless forced by large/smart customers' mandate for multiple source availability and a standard (like AES), I would see plenty of reason to do something simple to make my encryption scheme incompatible with other manufacturers so as to reduce competition (and sell more radios). To be clear, I have no idea if this is done, just that it makes sense.