Abstract: An innovative practical watermarking scheme for relational database based on character field was proposed in this paper. Identifying the target attribute values through the primary key, set of user keys and the span of watermark.Calculating the characteristics of attribute values and the watermark according to the defined rules and choosing those different bits as watermark bits. Semantic analysis gives a character, which is non-down structure and one of the most relevant attributes in the domain,and watermark embedding is the process of editing(insert/delete) the character. The embedded watermark is invisible and does not affect the availability of the database, and enables the blind extraction.The proposed scheme can achieve good excellent robustness to common database update such as insert, delete, modify and delete database fields.

Key words: Relational database, Digital watermarking, Structure of Chinese characters, Semantic analysis, Majority vote