Paper 2019/375

Secure Trick-Taking Game Protocols: How to Play Online Spades with Cheaters

Xavier Bultel and Pascal Lafourcade


Trick-Taking Games (TTGs) are card games in which each player plays one of his cards in turn according to a given rule. The player with the highest card then wins the trick, i.e., he gets all the cards that have been played during the round. For instance, Spades is a famous TTG proposed by online casinos, where each player must play a card that follows the leading suit when it is possible. Otherwise, he can play any of his cards. In such a game, a dishonest user can play a wrong card even if he has cards of the leading suit. Since his other cards are hidden, there is no way to detect the cheat. Hence, the other players realize the problem later, i.e., when the cheater plays a card that he is not supposed to have. In this case, the game is biased and is canceled. Our goal is to design protocols that prevent such a cheat for TTGs. We give a security model for secure Spades protocols, and we design a scheme called SecureSpades. This scheme is secure under the Decisional Diffie-Hellman assumption in the random oracle model. Our model and our scheme can be extended to several other TTGs, such as Belotte, Whist, Bridge, etc.

Available format(s)
Cryptographic protocols
Publication info
Published elsewhere. Minor revision. FC 2019
Trick-Taking GamesZero-KnowledgeSpadesBridgeCard Game
Contact author(s)
xavier bultel @ yahoo fr
2019-04-14: received
Short URL
Creative Commons Attribution


      author = {Xavier Bultel and Pascal Lafourcade},
      title = {Secure Trick-Taking Game Protocols: How to Play Online Spades with Cheaters},
      howpublished = {Cryptology ePrint Archive, Paper 2019/375},
      year = {2019},
      note = {\url{}},
      url = {}
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