New Watermarking Technique for Relational Databases

The need for watermarking database relations to deter their piracy, identify the unique characteristics of relational data which pose new challenges for watermarking, and provide desirable properties of a watermarking system for relational data. Proving ownership rights on outsourced relational databases is a crucial issue in today´s Internet-based application environments and in many content distribution applications. In this paper, new mechanism is proposed for proof of ownership based on the secure embedding of a robust imperceptible watermark in relational data. The steps of the proposed mechanism of watermarking relational database mainly involve decoding and encoding on numerical attribute of relational database. The first phase is to partition the original data and assign partition number to each and every tuple of the relation using cryptographic hashing function (MD5). In the second phase, while changing the data, select the desired watermark and bit bi is selected from the partitioned data and then that bit bi is changed using watermark W. When the original value of data gets changed due to the watermark bit, it always checks the data usability constraints. In the third phase, after inserting the watermark in the partition, merge all partitions and get the complete watermarked data. While decoding, use majority voting algorithm to get the correct watermark. Detecting the watermark neither requires access to the original data nor the watermark. The watermark can be detected even in a small subset of a watermarked relation as long as the sample contains some of the marks. Our technique also handles the attack on database like tuple deletion, alteration and insertion.