Secure Computation by Secret Sharing using Input Encrypted with Random Number

Keiichi Iwamura, Ahmad Kamal

2021

Abstract

Typically, unconditionally secure computation using a (k,n) threshold secret sharing is considered impossible when n<2k-1. Therefore, in our previous work, we first took the approach of finding the conditions required for secure computation under the setting of n<2k-1 and showed that secure computation using a (k,n) threshold secret sharing can be realized with a semi-honest adversary under the following three preconditions: (1) the result of secure computation does not include 0; (2) random numbers reconstructed by each server are fixed; and (3) each server holds random numbers unknown to the adversary and holds shares of random numbers that make up the random numbers unknown to the adversary. In this paper, we show that by leaving condition (3), secure computation with information-theoretic security against a semi-honest adversary is possible with k≤n<2k-1. In addition, we clarify the advantage of using secret information that has been encrypted with a random number as input to secure computation. One of the advantages is the acceleration of the computation time. Namely, we divide the computation process into a preprocessing phase and an online phase and shift the cost of communication to the preprocessing phase. Thus, for computations such as inner product operations, we realize a faster online phase, compared with conventional methods.

Paper Citation

in Harvard Style

Iwamura K. and Kamal A. (2021). Secure Computation by Secret Sharing using Input Encrypted with Random Number. In Proceedings of the 18th International Conference on Security and Cryptography - Volume 1: SECRYPT, ISBN 978-989-758-524-1, pages 540-547. DOI: 10.5220/0010552305400547

in Bibtex Style

@conference{secrypt21,
author={Keiichi Iwamura and Ahmad Kamal},
title={Secure Computation by Secret Sharing using Input Encrypted with Random Number},
booktitle={Proceedings of the 18th International Conference on Security and Cryptography - Volume 1: SECRYPT,},
year={2021},
pages={540-547},
publisher={SciTePress},
organization={INSTICC},
doi={10.5220/0010552305400547},
isbn={978-989-758-524-1},
}

in EndNote Style

TY - CONF

JO - Proceedings of the 18th International Conference on Security and Cryptography - Volume 1: SECRYPT,
TI - Secure Computation by Secret Sharing using Input Encrypted with Random Number
SN - 978-989-758-524-1
AU - Iwamura K.
AU - Kamal A.
PY - 2021
SP - 540
EP - 547
DO - 10.5220/0010552305400547