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
 発行年
 2023
to appearAbstract
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.