面向多方的密码系统基础问题研究

项目名称： 面向多方的密码系统基础问题研究

项目编号： No.60873232

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 金属学与金属工艺

项目作者： 徐秋亮

作者单位： 山东大学

项目金额： 34万元

中文摘要： 本项目系统地研究面向多方的密码系统中的基本问题。按照预定计划，深入研究了广播加密方案，分等级的基于身份加密方案（HIBE）；研究了环签名、并发签名协议及面向群体的签密方案。在多方协议的安全性分析中，分别采用标准模型，通用可组合框架等安全性证明结构，以及理性参与者模型，对提出的协议进行了精确的安全性分析。 本项目将研究内容向下层和上层扩展，延伸到面向多方密码系统的基础和应用研究。为了解决目前各类面向多方协议的一般性理论问题，结合密码学研究的前沿热点问题，我们深入地研究了安全多方计算协议，在公开或秘密模数约减等基本运算的实现及比特分解等工具性协议的设计方面取得一定突破；由于密钥协商协议的模型及分析方法，对于面向多方密码学有着典型代表性，其安全模型深刻体现着面向多方密码协议的特点，本项目也同时对密钥协商协议展开研究，并取得较多成果；最后，为了深入地理解并发展协议的证明方法，我们对零知识证明协议开展了一定研究。

中文关键词： 安全多方计算；广播加密；并发签名；群组密钥协商；零知识证明

英文摘要： This project presented a systematic study of the fundamental problems in multiparty oriented cryptography. According to the schedule, we investigated broadcast encryption, hierarchical identity-based encryption systems (HIBE), ring signature and concurrent signature, and group oriented signcryption schemes. Additionally, in the security analysis of multiparty protocols, we adopted the standard model, the universally composable framework, and the rational model respectively, and showed rigorous security analysis. Furthermore, we extended the research area of this project to a lower level as well as an upper level, to include the basic theory and the applications of multiparty oriented cryptosystem. First of all, in order to solve the general theoretical problems in multiparty oriented cryptography, we carried out a thorough research on secure multiparty computation following the frontier and hot problems in cryptography, and made an important breakthrough in realizing fundamental operations such as modular reduction by a public or private modulo, and designing efficient protocols for fundamental tools in secure multiparty computation, such as bit-decomposition. Moreover, since the security models and security analysis of key agreement protocols incorporate the idea from multiparty oriented cryptography, and in some sense reflect the characteristics of multiparty oriented protocols, we did an extensive research on key agreement schemes, and achieved plenty of results. At last, for further understanding and developing the proof techniques, we studied the theory and applications of zero-knowledge proof system.

英文关键词： Secure Multiparty Computation; Broadcast Encryption; Concurrent Signature; Group Key Agreement; Zero Knowledge Proof