PBMX is a framework to creating secure and fair games that can be played over
mail.
The main concern is supporting games that feature information that is *secret*,
*unknown*, or *unavailable* without the need for a trusted third party. Secret
information is information known to only a subset of the players; this could be
e.g. in a game of poker, the contents of a player's hand. Unknown information is
information that no player knows; in a game of poker, the contents of the deck
are unknown. Unavailable information is information that no player can obtain,
even at the end of the game; in a game of poker, the contents of the deck are
not only unknown but also unavailable, because revealing it even after the game
is over could show whether a player was bluffing or not.