Anyone know why I am not hearing Jackson Public Safety (Motorola) system? I see they have a second system coming up, but hear nothing on either one. Used to listen easily on handheld with stock antenna, now hear nothing with outdoor antenna?
Public Works, Animal Control and the Street Dept are all unencrypted. Police and Fire are ADP encrypted. No commercially available (AFAIK) scanner will decrypt their communications. However, it's not impossible to listen to them. Improbable or not likely may be more accurate, depending on several variables, but for all intents and purposes, it may just as well be impossible.
While the name "ADP" maybe Motorola proprietary, the cipher itself is not. Both Harris and Relm offer 40 bit ARC4 encryption which works fine with Motorola radios using ADP.
Harris Encryption Lite = ADP = Relm RCE
ADP does what it is supposed to do, keep the scanners and interlopers out. It's not intended to thwart more technical means of cryptanalysis or to protect sensitive, life-critical information. Or to protect information of high value.
Even being a paltry 40 bit cipher, there are still over a trillion possible keys.
So even at this lower security level, any attempt at key recovery from encrypted over-the-air transmissions still would require knowledgeable technical personnel with certain tools to be successful.
Unless there was a leak or the key selection was awful the above requirements stop the 99.9% of the masses from carrying out such an attack.