Abstract: Encryption technology has become an important mechanism of securing data stored in database.However，it is difficult to search efficiently the encrypted data and many researchers take it into consideration.To solve the problem，a novel way is proposed，we not only encrypt the character data by using the conventional encrypted algorithms，but also adopt the way of flatting and scrambling，and then store the translated characteristic values together with the encrypted data in the encrypted table.The approach can provide better security，and results of experiments validate the performance of our approach compared with the conventional approach.

Key words: database security, encrypted data, query, performance

摘要： 加密技术是保护数据库中数据安全的一种有效方法，但如何对加密数据进行高效查询是一个难点，引起了研究界的重视。针对这个问题，除了采用常规加密方法对字符数据进行加密外，还对字符数据进行扁平化和扰乱化处理，并把处理后的特征值作为附加字段与加密数据一起存储。该方法不仅安全性很好，而且通过实验证明其性能较传统方法有很大提高。

关键词: 数据库安全, 加密数据, 查询, 性能