国家政府机关和机密部门的重要文件，公司的核心业务和重要数据，以及高科技企业的研究数据、研究资料和研究成果，这些信息都是需要保证高度安全的。为了保证用户数据的安全，将数据加密存放到云端是很好的选择，如何在保证数据安全的条件下实现高效检索，这是本课题研究的核心。目前，国内外在全文检索技术、加密数据库、磁盘加密领域的研究已经趋向成熟，逐步进入实用环境。密文检索有三类，线性密文检索、基于索引的密文检索、基于同态加密的密文检索。而线性密文检索技术受限于用户数据安全和检索效率，发展仍然还有待进一步完善。针对这个问题，本文在传统的线性密文检索技术的基础上，对其安全性进行研究，并进行了改进，进一步设计和实现了该方案。主要工作包括：1 针对线性密文检索技术，研究了服务器端与客户端的数据加密实现方法，分析研究了加密与检索过程中的加密算法安全性、加密模式的安全性和随机数函数的安全性，改进了传统的线性密文检索技术。2 提出了按词量对分词进行动态填充的方案，大大降低了唯密文分析方法中的统计量，有效避免了ECB加密模式带来的安全性问题，无论是在单个词检索还是多个词的联合检索的检索效率方面，检索效率均保持在 不变。3 最后，在上述研究的基础上设计了一个可应用于云计算环境下的加密与密文检索原型系统。实现了完整的客户端加密、服务器端加密、密文检索与解密过程，从整体上分析了该系统的安全性，并对原型系统的加密和检索性能进行了分析。
Important documents of some government agencies and confidential department, core business data of the company and research data of high-tech enterprises, all the information is needed to ensure a high security. To ensure the security of user data, the data stored in the cloud encryption is a good choice. How to achieve efficient search, while ensuring the security of user data, which is the core of this research.At present, the researches in the full-text search technology, database encryption, disk encryption has been maturing, and gradually into the practical environment. Linear cipher-text retrieval technology is limited by the user data security and search efficiency, development remains to be further improved. Address this issue, on the basis of traditional lineal linear cipher-text retrieval technology, performed research and improve on is safety, design and implement the program. The main innovations are as follows.Research the data encryption implementations, analysis of the security of the encryption and the search process, improve the traditional search technology. Proposed the dynamically padding scheme based on words number, which avoid cipher-text-only statistical analysis methods and ECB encryption mode security issues. In the condition of single word or multi word, the search efficiency are maintained at . Based on the aforesaid search technology, we designed a cryptographic, secure and cipher-text search architecture under Cloud Computing. Then coding a prototype system. Achieve a complete client-side encryption, server side encryption and decryption and cipher text search process. Finally, from the overall analyzes its security, and the encryption and search performance of the prototype system.
