The original author said that "you aren't supposed to use them in aircraft."
Exactly. And he was wrong. There is not a problem with their use. Now, he was cool enough to accept being corrected, but you chose to go on arguing this silly point and exposed yourself as an asshole.
The prohibition comes from FCC regulations, not FAA.
Oh, wow, great (this, BTW, makes it an FCC rule, not "federal law" as you incorrectly asserted earlier.) And FCC is totally cool with such cell-phone use now, which makes their own, yours, and others' earlier assertions, that they are "dangerous" into dirty rotten lies. Congratulations, liar.
And you've been corrected now
No, dear. You have been corrected. Contrary to your assertions, the use of cellular phones inside airplane is harmless — whether or not there is a "federal law" against it is irrelevant. A pilot could use his personal phone — or some more convenient (and 10 times pricier) system using the same cellular network — to talk ATC as well as fellow pilots. Even that may be an improvement, but we don't have to stop there. By switching to TCP/IP we can make things much better (not just secure) for all — if only fewer people in aviation shared your stupid arrogant belief, that aviation has "unique" issues of its very own, which the outsiders have neither solved nor even encountered before.
so you should know better.
I do know better than some upstart, who thinks, his flight hours make him an expert in other walks of life.
So an ADS-B uplink that has 120 aircraft in its viscinity will actually retransmit every ADS-B packet from each aircraft 120 additional times?
Sure, why not? The numbers like 120 aren't at all impressive in the age of millions TCP connections per hour. A home-market WiFi router can handle more than 120 active wireless devices today — big deal...
And thus EVERYONE HAS TO HAVE THE KEY. Every aircraft needs that information.
Every craft needs the information, but they don't need each other's key — everyone just has to know a handful of mutually-trusted Certificate Authorities. Cryptography solved this problem decades ago.
Our military planes can each track dozens of both friendlies and non-cooperating hostiles — and share the information about the latter with the former — securely. A system to do the same with cooperating civilian aircraft and without concerns for enemy's jamming is not only possible, it is trivial.
And you would deliberately exclude every aircraft that has only "ADS-B in" capablility, because they just don't need to know any of this data?
People were flying without ADS-B for decades and mid-air collisions were extremely rare. But I would keep ADS-B installed for a while — as long as the plane's owner does not mind the privacy implications of it working. Perhaps, people would turn it on in busy airspace and off elsewhere.
(Unfortunately, your tone and manner make continuing this discussion too unpleasant. I'm unlikely to continue...)