【作者】 马辉；

【导师】 李金双；

【作者基本信息】 东北大学 ， 计算机系统结构， 2013， 硕士

【摘要】 随着信息技术和互联网的发展,用户对系统的安全性和功能设计要求不断提高。由于传统的公钥加密体制存在粗粒度访问控制策略以及效率低等缺点,难以适用于细粒度访问控制策略的密文管理。因此本文围绕具有细粒度访问控制策略的属性基加密(Atrribute-Based Encrytion, ABE)体制展开研究,并对其性能进行了优化改进。在此基础上,将改进的ABE方案应用于电子邮件系统中,使其在安全性方面具有机密性和完整性特点,在功能设计方面具有邮件单发及群发加密计算复杂度恒定的优点。本文具体工作和成果如下：在属性基加密体制研究方面,由于密文策略的属性基加密(Ciphertext-Policy Attribute-Based Encryption,CP-ABE)具有对密文细粒度访问控制的特点,因此本文对其重点展开研究。针对原始的CP-ABE方案的性能问题,研究了双线性配对的类型以及不同类型所具有的性能,提出了基于非对称双线性群的CP-ABE方案。定义了CP-ABE方案所使用的访问结构、门限、访问树结构、CP-ABE及其安全模型。进一步优化并改进了CP-ABE的解密算法的性能,使其具有更高效的解密算法。在基于CP-ABE电子邮件系统设计方面,针对传统电子邮件系统存在的完整性和机密性问题,以及现有加密电子邮件系统存在的邮件群发性能低问题,提出了基于CP-ABE的电子邮件系统。首先研究了电子邮件系统的工作原理；其次针对目前电子邮件系统存在的问题,分析了系统的设计目标；然后研究并提出了系统的体系结构,给出了基于CP-ABE的电子邮件系统的核心功能,包括系统初始化、解密密钥分发、邮件加密及发送和邮件接收及解密等。在基于CP-ABE电子邮件系统实现方面,基于上述的研究工作,首先对基于CP-ABE安全电子邮件系统中涉及的关键类进行了定义；然后给出了系统中各个功能的实现方法及过程；最后对设计实现的基于CP-ABE安全电子邮件系统原型进行了功能测试。该原型系统具有在邮件群发时加密算法计算复杂度为O(1)的优点。更多还原

【Abstract】 With the development of the information and internettechnology, the system security and functional design requirements continue to increase for the people. Because traditional public key encryption structure existscoarse-grained access control policies, and low efficiency, it is difficult to apply fine-grained access control policies ciphertext management. This papercentres on the research of the atrribute-based encryption (ABE)structure which has a fine-grained access control policies, and optimizes its performance. On this basis, the ABE program can be used in e-mail system, so that can be insure safety features with confidentiality and integrity, and in the functional design it has constantcomputational complexityfor a single and group e-mails encryption operation. This main works and results of this paper are as follows:On the research of attribute-based encryption structure, since ciphertext policy attribute-based encryption (CP-ABE) has the ciphertext fine-grained access control features, we focuses on its conduct research. For the original CP-ABE performance issues, we study the types of bilinear pairing with the performance of different types, and propose a new CP-ABE scheme based on asymmetric bilinear group. Then we define the notions of access structure, threshold and access tree structure, and claim the security model.of CP-ABE. Further, we optimize and improve CP-ABE decryption algorithm performance, such that it has a more efficient in the decryption algorithms.On the design of CP-ABE-based e-mail system, the traditional e-mail system has the integrity and confidentiality issues, and existing encrypted e-mail system existscomputation of low performance problem. Thus we first studied the principle of e-mail system; secondly for the current e-mail system problems, we analyze the system’s design goals; then study and propose architecture of the e-mail system based on CP-ABE scheme which our proposed, give the core of our e-mail system functions, including system initialization, the applyingand issuing of secret key, sending and encryptionof e-mail, receivingand decryptionof e-mail.On the implementationof CP-ABE-based e-mail prototype system, based on the above research work, we first define core classes of CP-ABE-based secure e-mail system; then we give the system realization methodsand processesof each function; Finally, based onthe design and implementation of CP-ABE-based secure e-mail system,we test and verify the functions of our prototype system.whensending group e-mails, our prototype system g algorithm complexity O(1).更多还原