A Distortion Free Watermark Scheme for Relational Databases

Database watermark is an effective solution to the piracy and data leakage problems. It is recognized as the final defense line in zero-trust architecture. Most of the traditional watermark schemes are based on carrier modification, which is difficult to achieve robustness while maintaining data quality. A new distortion free relational data watermark scheme is proposed, which guarantees data quality. Firstly, a watermark encoding algorithm is applied to combine bits in the data with the watermark information to generate auxiliary data, which is then stored. In the watermark extraction stage, the watermark decoding algorithm extracts the watermark information from the auxiliary data. The watermark capacity is greatly increased by encoding at least one attribute of each tuple. This does not modify the original data in any way and avoids the data distortion problems associated with traditional schemes. The experimental results show that the proposed scheme is more robust than traditional robust watermark schemes.