Abstract: With the development of cloud storage service, more and more data owners trend to outsource private data to the cloud data storage provider. To ensure the data security, data on the cloud server should be stored in the encrypted form. The existing multiple keywords ciphertext retrieval techniques cannot balance the accuracy and security. This paper presents a scheme based on the improved vector space model and homomorphic encryption technology. The performance analysis shows that the scheme can effectively solve the retrieval problem on ciphertext.

Key words: homomorphic encryption, Vector Space Model（VSM）, ciphertext retrieval, multiple keywords

摘要： 随着云存储服务的发展，越来越多的数据拥有者选择将数据外包给云服务商存储。为了保证数据的安全性，云服务器上的数据应该以密文形式存储。现有的多关键词密文检索技术不能兼顾准确性和安全性的问题，提出一种利用改进的向量空间模型和同态加密技术进行多关键词检索的方案。性能分析表明该方案能够有效地解决密文的多关键词检索问题。

关键词: 同态加密, 向量空间模型, 密文检索, 多关键词