Relational databases watermarking for textual and numerical data

Digital Watermarking may be used to protect databases copyright. A new method for proving the ownership of relational databases is presented. Such approach is applied for protecting both textual and numerical data. This is done by embedding special mark and watermark bits into textual attributes and numerical attributes respectively. Carriage return character and linefeed character, representing 1 and 0 of watermarking bits respectively, are inserted into textual data, which does not change original appearance and meaning of textual data in relational databases. For numerical data, Watermarks are embedded into one of least significant bits (LSB) of the optional attributes. Our method is suitable for watermarking some numerical data, and all textual data with arbitrary number of words. Watermark extraction does not require original data. Experiments show that even the database suffers from approximately 70% of addition, alteration and deletion attacks, our method can achieve above 95% extraction rate of watermark.