Public-PEZ Cryptography

Soma Murata, Daiki Miyahara, Takaaki Mizuki, Hideaki Sone

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

4 Citations (Scopus)


Secure multiparty computation (MPC) is a cryptographic technique that enables us to evaluate a predetermined function over players’ private inputs while hiding information about the inputs. MPC can be conducted using a “private PEZ protocol,” that uses PEZ candies and a dispenser. Specifically, in a private PEZ protocol, players first fill a predetermined sequence of candies in a dispenser. Then, each player in turn privately pops out a number of candies, wherein the number depends on their private input (without anybody else knowing how many candies pop out). The next candy to be popped out of the dispenser indicates the output value of the function. Thus, private PEZ protocols are fun and useful. One drawback would be that every player must pop out candies from the dispenser secretly, implying that a private PEZ protocol is vulnerable to dishonest players, for example, a player could peep the candies inside the dispenser. To overcome this drawback, we herein propose MPC protocols that do not need private actions such as secretly popping out candies after the setup (although each player rearranges the candies secretly in a setup phase, any illegal actions can be caught). That is, we construct a computational model of “public-PEZ cryptography,” where any protocol within the model can be publicly executed. Especially, the proposed public-PEZ AND protocol, which uses only five candies and two dispensers, is simple and easy for conducting a secure computation of the AND function.

Original languageEnglish
Title of host publicationInformation Security - 23rd International Conference, ISC 2020, Proceedings
EditorsWilly Susilo, Robert H. Deng, Fuchun Guo, Yannan Li, Rolly Intan
PublisherSpringer Science and Business Media Deutschland GmbH
Number of pages16
ISBN (Print)9783030629731
Publication statusPublished - 2020
Event23rd International Conference on Information Security, ISC 2020 - Bali, Indonesia
Duration: 2020 Dec 162020 Dec 18

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume12472 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349


Conference23rd International Conference on Information Security, ISC 2020


  • Card-based cryptography
  • Private PEZ protocols
  • Recreational cryptography
  • Secure multiparty computations


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