Cryptochain mode is used in pier-to-pier and multi-user games. Players’ moves are interconnected move-by-move into an encrypted chain by means of unidirectional Hash function and server’s CryptoKey generated at game start.
In responce to her move, the player gets a game state at the moment the move was counted in the game AND an Open Code with encrypted information about all moves placed in the game by that moment. At game end, the server discloses the CryptoKey, the move timing record and the Open Code timing record, so that anyone can check the Fair Play Criterion at any playing moment.