I'm going to believe the report that earpieces, etc are a distraction. That's too obvious. If I was viable we wouldn't have this thread.
That random number generator (or authenticator to anyone who's ever played an MMO) actually sounds like a really good idea, provided there's access to an easy cheat sheet or something and it's quick.
Only, if you're going to go that far, just send the signals instead, right? It seems to be the same amount of distraction, unless I misunderstood how often it changes. If it's every pitch, then pitcher and catcher both have to check it every time anyway. If it's not, how hard could it be to catch into which number it is and adjust? Another thing an algorithm can just do for you. That just the same situation with extra steps.
Just call the pitches from that same device. I'm really not worried about hacking. Some basic encryption should suffice, especially if it has to connect to a third party in between. They're doing what they're doing now as a function of opportunity. If you go this route, it's far too prohibitive for such a small gain. Not to mention, hacking an opposing team to gain a competitive edge has to be a long way away from the gray area sign stealing sits in. People would just move on to the next best advantage they could find and we'd basically render the entire concept of sign stealing obsolete.