Getting nature to roll a dice

I have a new addiction.

Pod casts.

The last one I listened to was talking about encryption methods. The simple method discussed worked by having a key which would decipher an encrypted message.

An example:

The encrypted message is "BLA".

The key is "2 3 6".

To solve the message you would count 2 letters on from B, 3 letters on from L and 6 letters on from A in the alphabet. This gives you the word "DOG". Pretty cool right?

Now we can start getting fancy. For example instead of an alphabet you could use a QWERTY keyboard or you could assign integer values to words, names or letters to make your key a riddle in itself.

Two things come to mind for me.

Firstly, this is the first practical application of Sterling numbers that I've bumped into. Or am I thinking of the modulus of a number!? I'll look it up!

Secondly, I could spend all day trying to think of ways to make the key interesting! I instantly thought how cool it would be if there was a way in which you could have a seemingly random event decide the key to use for the day.

For instance, all allies could set their watches to the same time. They decide on a random event that occurs each day, but one which they all would be aware of when it happens. If the event happens at 13:22, then the key for the next day could be 1 3 2 2, cycling through the numbers as need be. What could such an event be? A sound? A sight? How about the time at which a shop owner has his first customer with a red shirt? Or maybe even use the closing price of some arbitrary stock on a random stock exchange half way around the world? Maybe they could send an encrypted text message and the key would be the time at which they send it. Geesh! So many options!

There's a card game I like to play where you and your team mate have to have a secret sign to communicate to each other when one of you has four-of-a-kind. This is achieve through a simple method of exchanging cards with the dealer and other players. Once you have four of the same cards you need to let your partner know without letting the other team know. If you can do this successfully without being busted then you win. The other way to win is to bust the opposition team when they are trying to do the same. The typical signs are finger taps and head scratches. These kinds of signs have to be done quickly and subtly to avoid being picked up by your opposition. I always tell my partner beforehand that our sign should be this: trying to bust the other team, accusing them of blinking suspiciously... or something else that they would naturally have to do. Chances are that we would be wrong and their sign wouldn't be that obvious, however we would use this decoy as our sign to each other that we're ready to lay our cards out and collect our bragging rights.

It's all it is at some level. It's a game.