Who *shouldn't* see the info?
SoCalBrian writes about keeping ADS-B communications private.
Private from whom, exactly?
The whole point of ADS-B is to broadcast aircraft position information so that planes can avoid each other. Who do you not want to have this information?
Considering that any aircraft, down to the smallest LSA, should be able to both broadcast and receive ADS-B info, any "bad guys" you might want to keep away from the info could simply, legitimately, buy or rent an LSA, and have all the info available. I do not see how encryption can work in a system where the whole point is to let others know where you are.
How does sending ADS-B out to only "good guys" work, when the "bad guys" can become "good guys" for the price of an LSA rental? (or even less?)