ROYALE: a framework for Universally Composable card games with financial rewards and penalties enforcement

Bernardo David, Rafael Dowsley, Mario Larangeira

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While many tailor made card game protocols are known, the vast majority of those lack three important features: mechanisms for distributing financial rewards and punishing cheaters, composability guarantees and flexibility, focusing on the specific game of poker. Even though folklore holds that poker protocols can be used to play any card game, this conjecture remains unproven and, in fact, does not hold for a number of protocols (including recent results). We both tackle the problem of constructing protocols for general card games and initiate a treatment of such protocols in the Universal Composability (UC) framework, introducing an ideal functionality that captures card games that use a set of core card operations. Based on this formalism, we introduce Royale, the first UC-secure general card games which supports financial rewards/penalties enforcement. We remark that Royale also yields the first UC-secure poker protocol. Interestingly, Royale performs better than most previous works (that do not have composability guarantees), which we highlight through a detailed concrete complexity analysis and benchmarks from a prototype implementation.

Original languageEnglish
Title of host publicationFinancial Cryptography and Data Security
Subtitle of host publication23rd International Conference, FC 2019 Frigate Bay, St. Kitts and Nevis, February 18–22, 2019 Revised Selected Papers
EditorsIan Goldberg, Tyler Moore
Place of PublicationCham Switzerland
Number of pages19
ISBN (Electronic)9783030321017
ISBN (Print)9783030321000
Publication statusPublished - 2019
Externally publishedYes
EventFinancial Cryptography and Data Security Conference 2019 - St Kitts, St Kitts and Nevis
Duration: 18 Feb 201922 Feb 2019
Conference number: 23rd (Website) (Proceedings)

Publication series

NameLecture Notes in Computer Science
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349


ConferenceFinancial Cryptography and Data Security Conference 2019
Abbreviated titleFC 2019
CountrySt Kitts and Nevis
CitySt Kitts
Internet address

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