安全协同计算中群密钥的同态提取与通用构造

By extending the well-known DH key agreement protocol, it is difficult to address the essential concerns, one-round and self-organized group key agreement (GKA), for secure group communications in the latest collaborative applications. Typical examples of this type applications are cloud computing and MANETs. In this project, with key-homomorphic encryption\signcryption theories and new fast public-key cryptosystems, we concentrate on the new design theory and the general construction of one-round self-organized GKA protocols for the latest distributed collaborative computing. Our major research contents are as follows: .Firstly, we use the key-homomorphism of some fast lattice public-key encryption algorithms and some certificateless signature algorithms to construct the combined algorithms of group encryption public keys and the extract algorithms of members' decryption keys. And then we will achieve a one-round self-organized GKA protocol and its general constructions based on key-homomorphic cryptosystems. .Secondly, we further focus on the certificateless authenticity of one-round self-organized GKA protocols by constructing recursive key-chains and group key encapsulation algorithms respectively based on signcryption Tag-KEM and key-homomorphic signcryption. We also prove that the proposed one-round GKA protocols are secure in the outsider unforgeability notion and the insider unforgeability notion. .Last but not least, we research on the adaptation of one-round self-organized GKA protocols to dynamic group events. What this means is minimizing the influence from group key update on other members. .Since our research emphasizes both theory originality and application effectiveness, we believe that the main achievements of this project can provide a theoretic basis and a new design reference for secure group communication and confidential channel pre-establishment in the latest large-scale distributed collaborative computing.

扩展DH协议这一传统研究方法难以获得新型协同计算安全所必需的一轮自组织群密钥协商协议，本项目基于密钥同态性密码算法和秘密分割理论，研究安全协同计算中一轮自组织群密钥协商协议的新型设计理论和通用构造。具体包括：利用密钥同态性新型格公钥加密和密钥同态性无证书签名，求解公钥合并与群密钥提取关键科学问题，进而构造出一轮自组织群密钥协商协议，并提出基于密钥同态性密码算法构造一轮自组织群密钥协商协议的一般方法；研究一轮群密钥协商协议的无证书认证性，通过签密Tag-KEM和密钥同态性签密分别构造递推密钥链和群密钥封装算法，设计出抗公钥替换攻击安全的且具有内外部不可伪造性的一轮自组织群密钥协商协议；研究一轮自组织群密钥协商协议对动态群事件的适应性，降低动态群密钥更新对群成员的影响。该项研究注重理论原创性与应用实效性，研究成果将为新型分布式协同计算中的安全群通信和安全信道预先建立提供基础设计理论和方法参考。

基于扩展DH协议这一传统技术路线难以获得新型协同计算安全所必需的一轮自组织群密钥协商协议。本项目基于密钥同态性密码算法和秘密分割理论，研究一轮自组织群密钥协商协议的新型设计理论和通用构造，为群密钥协商协议的设计引入了一些新的构造理论，解决了基于密码算法密钥同态性的群密钥提取及其认证性两个关键科学问题。主要研究成果包括：提出了基于密码算法的密钥同态性构造公钥合并与群密钥提取算法的通用构造，并在此通用构造框架内具体设计了多种应用场景下的一轮自组织的群密钥协商协议；基于签密与密钥管理在机理上的联系，构造群密钥提取算法并设计了具有双向认证性的群密钥协商协议；设计了具有无证书认证性的一轮自组织群密钥协商协议；在群密钥协商算法的设计中嵌入承诺，同时实现了群消息的机密性和不可否认性；针对容延容断网络(DTNs)，基于网络的空时演化规律并结合双信道密码学实现了密钥交换协议的非交互性和认证性，以及时延和中断容忍性。这些研究成果已获得国内外同行关注，数篇论文被国内外同行多次引用。