TTP-Aided Secure Computation Using (k, n) Threshold Secret Sharing With a Single Computing Server

Abstract

Secure computation can be divided into those using homomorphic encryption and secret sharing. The advantage of the former method is that the computation can be performed on a single computing server and the computation process can be made public if the encryption key used is securely managed. However, the latter is computationally light and capable of high-speed processing, but it requires multiple independently managed computing servers, and processes of $k$ or more servers cannot be disclosed. When considering a business model for implementing secure computation that uses secret sharing, private information can be leaked if computing servers are managed by the same organization. Therefore, we need a complex business model in which multiple companies without conflicts of interest manage each computing server independently and make a profit. However, this approach is difficult to implement in practice. In this study, we proposed a secure computation using secret sharing. Moreover, by effectively using TTP, we demonstrated that it is possible to realize secure computation with a single computing server. In addition, we demonstrated that, if the security keys used are securely managed, the entire computational process can be made public. In other words, we realize a method that addresses all the drawbacks of the aforementioned methods, and it is possible to realize faster and more secure computations than conventional methods using secret sharing.

Keywords

• Secure computation
• secret sharing
• multiparty computation
• trusted third party
• fast processing