混合偏好模型下的分布式理性秘密共享方案

A Distributed Rational Secret Sharing Scheme with Hybrid Preference Model

理性秘密共享方案通过扩展参与者的类型后具有更好的适应性,而现有方案中的共享秘密往往依赖于秘密分发者,但在某些特定环境中秘密分发者并不一定存在.通过对传统分布式秘密共享方案的分析,给出了分布式理性秘密共享方案的一般形式化描述;同时,考虑理性参与者的眼前利益和长远利益,提出一种新的理性参与者混合偏好模型;进一步结合机制设计理论的策略一致机制,设计了一个激励相容的信誉讨价还价机制,以此有效约束理性参与者的行为,从而实现了公平的(t,n)(t,n≥2)分布式理性秘密共享方案的构造;通过从信道类型、秘密分发者的在线/离线需求、方案的通用性和偏好模型等方面与目前相关理性秘密共享方案进行对比分析,进一步分析了所提出方案的优势.

In traditional secret sharing schemes, players are either honest or malicious. An honest player follows the protocol perfectly but a malicious player always deviate from the protocol. However, players＇ behavior is selfish and they follow the protocol only if their expected utility is satisfied in rational secret sharing scheme. In that sense, rational secret sharing has more applicability. In the existence of rational secret sharing schemes, the preference models only focus on immediate interests or long-term interests, and the secret＇s distributions rely on the dealer. But such dealer may not exist in some special settings. After analyzing the traditional distributed secret sharing schemes, a general formalization of distributed rational secret sharing scheme is proposed. In our setting, a new hybrid preference model which simultaneously considers the immediate interests and the long-term interests of rational participants is discussed. Meanwhile, combining with the strategy- proof mechanisms of mechanism design theory, the bargaining reputation mechanism is designed with the incentive compatibility, which is effectively to restrict the behavior of the rational players, so that a fair （t,n） （t,n≥2） distributed rational secret sharing scheme is realized. Finally, some advantages of our scheme are showed by comparing with current rational secret sharing schemes in communication channel types, the requirement of on-line or off-line dealer, universality and the rational players＇ preference model.