A method of bucket index over encrypted character data in database

The encryption mechanism is the common method to protect the sensitive data in database from various attacks. But once the data in databases is encrypted the efficiency of DBMS will fall. To enhance the security of the sensitive data and to improve the efficiency of the encrypted database, one effective method is to build index on the encrypted field and firstly executes the query on the index to get fewer records to decrypt in this paper. This paper proposes an index mechanism of bucket index on the character data, which has close relationships with all of its characters. The index tries to translate the character string into a numeric data, on which the primary query will be processed to filtrate the records roughly. Only the rest records need to be decrypted, and it will save lots of time. So the cipher index can improve the query efficiency greatly.