Database Watermarking Algorithm Based on Difference Expansion

Database watermarking technology is an important means to protect database information security. Firstly, the key components of the database are divided into several sub-groups by using the key hash function. Then, the size of the Pearson correlation coefficient is used in the sub-group to be selected the attribute column to be embedded in the watermark, and then the threshold is set by the differential expansion algorithm to determine the final embedded watermark. The pair of attributes, embedding in the virtual watermark repeatedly in the position that satisfies the condition. By setting the threshold, the embedding amount of the watermark is reduced, and the robustness of the watermark is improved. The loss of the original data of the database is guaranteed, and the watermark and the watermark extraction rate are better when attacked. When the attack ratio is low, the data recovery effect is better.