Semi-Fragile Watermarking Scheme for Relational Database Tamper Detection

摘要

Most of data over the internet today is hosted on outsourced third party servers which are not trusted. Data on these servers may be tampered easily; hence, there is a need of some mechanism to verify database integrity. Particularly, the authentication process should be able to differentiate between legal updates and malicious modification. In this paper, we present a novel semifragile watermarking scheme for relational database integrity verification. Besides detection and localization of database tampering, the proposed scheme allows modifications to the data that need periodic updates, without requiring re-watermarking. Watermark embedding is distortion free, as it is done by adjusting the text case of selected data values. This retains semantic meaning of data. Additionally, group based embedding ensures the localization of tampering to group level. We built a proof of concept application of our watermarking technique. Experiments show that even a single value modification can be detected with very high probability besides detection of attacks like tuple insertion and tuple deletion