Why don’t NFL teams encrypt their signals better?
Football fans know that the Patriots got busted stealing signals from the Jets the other week. My initial reaction was: why just fine the Patriots rather than a meaningful penalty, like forfeiting the game? But I think Ed Felten, a computer professor at Princeton, asks an even better question, “why don’t NFL teams encrypt their signals better?” (As aside, this blog is amazing in that every response is worth reading too.)
Of course, there are challenges: the game clock keeps ticking, players are traded to rival teams and signals have to be transmitted in open view of cameras and the public. And the players involved are not brain surgeons!
The most prevalent solutions currently used involve secrecy and timing. Think of the third base coach: he makes lots of irrelevant signals, and then at some point he gives an indicator signal and then the next few ones are the real signals. Part of the security comes from the fact the opposition doesn’t know what a real signal is (e.g., is the left foot forward or the right hand scratching the ear?) This is a simple encryption scheme that can easily be deciphered with enough observations. Here’s a short youtube interview of minor league third=base coach:
In football, Ed suggests a better solution: a “one-time use pad.” For example, defensive players can have a grid with the various defenses on it. The coach just sends two signals, one for the row and one for the column. It doesn’t matter if the opponents know what the system is or the signals, so long as the pads are secret. And the pads can be disposed or replaced several times in a game. All of the crypyographic work can be done by computers and experts on the sidelines.
So when will sports teams start hiring cryptographers? First, they could protect their own teams signals. Second they could probably crack the opponents systems as well until they hire their own experts!