Instantaneous Decentralized Poker
This work addresses the challenge of secure and scalable decentralized financial applications, such as poker, for users in cryptocurrency networks, representing an incremental improvement over existing payment channel technologies.
The paper tackles the problem of enabling efficient, secure decentralized poker games by introducing protocols for amortized secure multiparty computation with penalties and cash distribution, leveraging stateful contracts to allow parties to interact only among themselves after an initial cryptocurrency setup, resulting in more efficient and feature-rich implementations compared to Bitcoin-based methods.
We present efficient protocols for amortized secure multiparty computation with penalties and secure cash distribution, of which poker is a prime example. Our protocols have an initial phase where the parties interact with a cryptocurrency network, that then enables them to interact only among themselves over the course of playing many poker games in which money changes hands. The high efficiency of our protocols is achieved by harnessing the power of stateful contracts. Compared to the limited expressive power of Bitcoin scripts, stateful contracts enable richer forms of interaction between standard secure computation and a cryptocurrency. We formalize the stateful contract model and the security notions that our protocols accomplish, and provide proofs using the simulation paradigm. Moreover, we provide a reference implementation in Ethereum/Solidity for the stateful contracts that our protocols are based on. We also adopt our off-chain cash distribution protocols to the special case of stateful duplex micropayment channels, which are of independent interest. In comparison to Bitcoin based payment channels, our duplex channel implementation is more efficient and has additional features.