Persistent Watermarking of Relational Databases

Digital watermarking for relational databases emerged as a candidate solution to provide copyright protection of relational data, maintaining integrity of the database information, tamper detection, traitor tracing etc. In this paper, we introduce the notion of persistent watermarking that serves as a way to recognize the integrity and ownership proof of the database bounded with a set of queries. It allows the evaluation of the database while applying the queries. We preserve the persistency of the watermark by exploiting two invariants of the database state w.r.t. the set of queries: Stable Cells and Semantics-based Properties of the data. We discuss how we can improve the existing techniques in terms of the persistency of the watermark. Moreover, we propose a novel persistent watermarking scheme that strictly improves the algorithm proposed by Li and Deng