Card-based ZKP protocols for takuzu and juosan

Daiki Miyahara, Léo Robert, Pascal Lafourcade, So Takeshige, Takaaki Mizuki, Kazumasa Shinagawa, Atsuki Nagao, Hideaki Sone

Research output: Chapter in Book/Report/Conference proceedingConference contribution

15 Citations (Scopus)


Takuzu and Juosan are logical Nikoli games in the spirit of Sudoku. In Takuzu, a grid must be filled with 0's and 1's under specific constraints. In Juosan, the grid must be filled with vertical and horizontal dashes with specific constraints. We give physical algorithms using cards to realize zero-knowledge proofs for those games. The goal is to allow a player to show that he/she has the solution without revealing it. Previous work on Takuzu showed a protocol with multiple instances needed. We propose two improvements: only one instance needed and a soundness proof. We also propose a similar proof for Juosan game.

Original languageEnglish
Title of host publication10th International Conference on Fun with Algorithms, FUN 2021
EditorsMartin Farach-Colton, Giuseppe Prencipe, Ryuhei Uehara
PublisherSchloss Dagstuhl- Leibniz-Zentrum fur Informatik GmbH, Dagstuhl Publishing
ISBN (Electronic)9783959771450
Publication statusPublished - 2020 Sep 1
Event10th International Conference on Fun with Algorithms, FUN 2021 - Favignana Island, Sicily, Italy
Duration: 2021 May 302021 Jun 1

Publication series

NameLeibniz International Proceedings in Informatics, LIPIcs
ISSN (Print)1868-8969


Conference10th International Conference on Fun with Algorithms, FUN 2021
CityFavignana Island, Sicily


  • Card-based cryptography
  • Juosan
  • Takuzu
  • Zero-knowledge proof

ASJC Scopus subject areas

  • Software

Cite this