,
Pascal Lafourcade
,
Maxime Puys
Creative Commons Attribution 4.0 International license
Card-based zero-knowledge proof (ZKP) protocols allow a prover to convince a verifier that it knows a witness of a given statement, without revealing any information, using a physical deck of playing cards. Previous studies have focused on puzzles with a specific connected component, such as a simple cycle and a polyomino. In this study, we propose a unified approach to handle a family of connected components, including a tree, path, cycle, and polyomino. This approach achieves this verification in O(mn) steps relative to a given grid size m × n. Using this approach, we construct a card-based ZKP protocol for Nurimeizu, where the goal is to find the shortest path on a given grid.
@InProceedings{miyahara_et_al:LIPIcs.FUN.2026.35,
author = {Miyahara, Daiki and Lafourcade, Pascal and Puys, Maxime},
title = {{Card-Based ZKP Protocols for Connectivity-Based Puzzles: Extending to Tree Structures with Application to Nurimeizu}},
booktitle = {13th International Conference on Fun with Algorithms (FUN 2026)},
pages = {35:1--35:13},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-417-8},
ISSN = {1868-8969},
year = {2026},
volume = {366},
editor = {Iacono, John},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.FUN.2026.35},
URN = {urn:nbn:de:0030-drops-257547},
doi = {10.4230/LIPIcs.FUN.2026.35},
annote = {Keywords: Card-based cryptography, Nurimeizu, Nikoli, ZKP}
}