学術論文誌

A Computationally Efficient CardBased Majority Voting Protocol with Fewer Cards in the Private Model
 著者
 Y. Abe, T. Nakai, Y. Watanabe, M. Iwamoto, and K. Ohta
 雑誌名
 IEICE Transactions on Fundamentals
 巻
 E106A
 号
 3
 ページ
 315–324
 出版社
 IEICE
 発行年
 2023
Abstract
Cardbased cryptography realizes secure multiparty computation using physical cards. In 2018, Watanabe et al. proposed a cardbased threeinput majority voting protocol using three cards. In a cardbased cryptographic protocol with nbit inputs, it is known that a protocol using shuffles requires at least 2n cards. In contrast, as Watanabe et al.'s protocol, a protocol using private permutations can be constructed with fewer cards than the lower bounds above. Moreover, an ninput protocol using private permutations would not even require n cards in principle since a private permutation depending on an input can represent the input without using additional cards. However, there are only a few protocols with fewer than n cards. Recently, Abe et al. extended Watanabe et al.'s protocol and proposed an ninput majority voting protocol with n cards and n + \floor{n/2} + 1 private permutations. This paper proposes an ninput majority voting protocol with \ceil{n/2}+1 cards and 2n1 private permutations, which is also obtained by extending Watanabe et al.'s protocol. Compared with Abe et al.'s protocol, although the number of private permutations increases by about n/2, the number of cards is reduced by about n/2. In addition, unlike Abe et al.'s protocol, our protocol includes Watanabe et al.'s protocol as a special case where n=3.