Character Mapping Cipher Index Scheme for Character Data in Outsourced Databases

Cipher index is a well established technology for improving query efficiency. But existing cipher index schemes are aimed at numeric data. Thus, a Character Mapping Cipher Index Scheme applied to ODBs is presented to solve accurate query on cryptogram, which allows various key word and fuzzy queries. This scheme firstly determine all the characters composed the domain of attribute, then assign a unique character index to each character through mapping function. As a result, the cipher index is formed through contacting character indices with random characters approximately. Furthermore, its performances are analyzed. Finally, the cryptograph query strategy on ODBs is presented.