1) I am wondering whether a "digital deck of cards" is a good choice. Premature abstraction is a severe problem if it happens to you. Read some of the literature to get an idea of the techniques before you pick an abstraction. Your remarks about knowledge models for an abstraction proposal of "a table with stacks of cards" seem on target. Most card games require a random permutation, mutually trusted to be random, which can be revealed one card at a time. That permutation need not be generated in advance. Games like Magic--The Gathering in which each player shuffles their own deck, are easier to implement and only require bit committment. The revealing of cards cannot be global, since at the beginning each player sees only their own cards. The revealing of cards should require that the cooperation of each player that sees the cards, and possibly some others. Time to read crypto. Eric