Some good answers here, something else I'd like to put out there to you all
In one-off dice games, where there is a single bitcoin transaction used per game.
Would the transaction ID be an acceptable seed for generating a winning number?
Or are transaction id's predictable/manipulatable ?
Thanks!
Satoshidice also uses a daily secret. You can manipulate your transaction hash to a certain extent, such as not broadcasting one, redo it, then broadcast that one for whatever reason. But combined with a site secret, your roll effectively becomes random.
SD was one of the first blockchain based dice games. It's method is the gold standard.