面向云存储的多机构属性加密技术研究

The cloud storage service, as a significant application of cloud computing techniques, cannot only significantly reduce the storage costs for data owners, but also efficiently realize data sharing among different users. However, in a cloud storage system, once the data owners store local data in the cloud, they inevitably lose control over the data, and this may cause the reveal of the data. Multi-authority attribute-based encryption is a promising encryption technique for data confidentiality and fine-grained access control in a cloud storage environment. According to the application and security requirements of cloud storage, this project makes a further study on the efficiency, security and functionality in multi-authority attribute-based encryption. Firstly, we will construct an efficient multi-authority attribute-based encryption scheme, which can help to reduce the huge computational and storage overhead for users. Secondly, we will design the traceable and revocable multi-authority attribute-based encryption scheme, which can be used to solve the key abuse problem in the cloud storage system. Thirdly, we will study the multi-authority attribute-based encryption scheme with keyword search, which can achieve data confidentiality, access control and ciphertext retrieval simultaneously. The achievements of this project will provide theoretical basis and technical support for the application of multi-authority attribute-based encryption in the cloud storage service, which can advance the application and development of cloud computing.

作为云计算技术的一个重要应用，云存储技术不仅能够大大减少数据拥有者的本地存储开销，还能够高效实现用户间的数据共享。然而，在云存储系统中，数据拥有者将本地数据存储在云端，失去了对数据的控制，这极易造成用户数据泄露。多机构属性加密技术被认为能够有效实现云存储数据安全和灵活访问控制。针对云存储的应用和安全需求，本项目对多机构属性加密的效率、安全性和功能展开深入研究。第一，构造高效多机构属性加密方案，减轻用户巨大的计算和存储负担；第二，设计支持用户追责与撤销的多机构属性加密方案，解决云存储系统中的用户私钥滥用问题；第三，研究支持关键词检索的多机构属性加密方案，同时实现数据安全、访问控制和密文检索功能。本项目研究将为多机构属性加密在云存储服务中的应用提供理论依据和技术支撑，推动云计算技术的应用与发展。

本项目着重围绕云存储中的应用和安全需求，为数据保护和高效共享提供解决方案，主要研究属性加密及其应用，设计了多个具有不同性能优势的密码算法。主要成果包括：（1）构造了支持用户追责和撤销的多机构属性加密方案，且在数据访问过程中仅需6个双线性对运算。（2）设计了基于属性加密的并联关键词检索方案。所提方案同时支持细粒度检索控制和并联关键词检索。（3）构造了同时支持策略隐藏，用户追责和撤销的基于属性的关键词检索方案。所提方案不仅可以确保关键词和访问策略的机密性，而且可以对恶意用户进行追责。（4）基于密文策略属性加密提出一个可验证数据聚合方案，所提方案支持用户撤销和外包解密。（5）提出一个高效的完整验证方案，所提方案可以保护云数据的隐私性和完整性。本项目研究成果为属性加密在云存储服务中的应用提供理论依据和技术支撑，有助于云计算技术的应用与发展。截止目前，项目组共发表学术论文8篇，申请国家发明专利1项。