Well, nobody said nothing about cracking AES 256
Other than that, even if the type of encryption was the same, you can't compare 15 bit key with a 256 one
The whole thing is that NXDN standard include those 32766 keys by default. They are there, in the radio. It's like analog radio, where those type of 'security' measures are in the menu of the transciever. The only difference is that NXDN is doing this digitally. Like AES came to this world to replace DES, digital scrambler came here to replace the analog one (who knows what's coming one day to replace AES and all those other fancy encryption methods)
And since they are in the radio it is a matter of time (a lot of time, and maybe even not enough if they change it regularly) to test them all and find the right one if you want. AOR receiver just do it easily for you
And let me point that I do not push anybody into illegal actions neither I am looking for a way to break the encryption! I was just wondering the way those receivers act - do they scan it only when they are receiving live signal or do they have an option for post processing a recorded one since they have the ability to record baseband audio. That's all
It's up to the user to "think before act" and should you act if you have the ability to do it