A new entropic criterion model in rational secure two-party computation

Abstract

Rational secure two-party computation is one of the important researches in cryptography. Since the purpose of rational parties is to maximize their own utilities, the parties prefer to use a mixed strategy, which will cause a change in entropy. Some protocols solved the problems of fairness and security by using entropy function and utility function respectively. However, the cost of ensuring protocol security by setting a really high utility function is often higher than the value of the protocol itself, and the protocol is only suitable for a single privacy requirement. In this paper, we propose a secure two-party computation protocol based on entropic criterion and set the corresponding security entropic threshold according to different privacy requirements. Secure entropy is used as a method to evaluate the security of two parties in different scenes. Furthermore, we explore the relationship between secure entropy and utility function, then to select the optimal utility function within the range of secure entropic threshold. The model we proposed is more flexible and universal. Furthermore, the security state of the model is well predicted.