Kaleidoscope: An Efficient Poker Protocol with Payment Distribution and Penalty Enforcement

The two main challenges in deploying real world secure poker protocols lie in enforcing the distribution of rewards and dealing with misbehaving/aborting parties. Using recent advances in cryptocurrencies and blockchain techniques, Kumaresan et al. (CCS 2015) and Bentov et al. (ASIACRYPT 2017) were able to solve those problems for the general case of secure multiparty computation. However, in the specific case of secure poker, they leave major open problems in terms of efficiency and security. This work tackles these problems by presenting the first full-fledged simulation-based security definition for secure poker and the first fully-simulatable secure poker protocol that provably realizes such a security definition. Our protocol provably enforces rewards distribution and penalties for misbehaving parties, while achieving efficiency comparable to previous tailor-made poker protocols, which do not have formal security proofs and rewards/penalties enforcement. Moreover, our protocol achieves reduced on-chain storage requirements for the penalties and rewards enforcement mechanism.