International Journal of Computer Applications (0975 – 8887) Volume 88 – No.6, February 2014 5 A New Technique for Relational Database Protection Nahla El_Haggar Faculty of Computers & Information Helwan University, Egypt Mahmoud M. El-khouly Faculty of Computers & Information Helwan University, Egypt Samah S. Abu El Alla Faculty of Computers & Information Helwan University, Egypt ABSTRACT The great development of computer technologies and the Internet have made duplication and distribution of digital information simpler. This leads to a need for effective copyright protection tools. Watermarking database system is considered a vital technique for copyright protection of database systems. In this paper the proposed system is a robust technique to embed and detect watermark in a relational database. In the embedding watermarking stage the watermark is embedded in non numeric attributes for preserving the query results, then is compressed the database for increasing the transfer rate. In watermark detection stage the database will be decompressed, and then the distortion of the embedding watermark will be checked to identify pirated copies of original data. The proposed technique is considered a fully blind and has robustness against various types of attacks specially deletion and sub selection attack. General Terms Security, Relational Database, Watermarking. Keywords Relational database system; copyright protection; watermarking; non numeric attribute; database attacks 1. INTRODUCTION Nowadays, the using of relational database systems is increased in many real-life applications; copy relational database and redistribute illegal copies become very easy. Therefore, copyright protection of database systems becomes very important research area. It identifies pirated copies of original data. It doesn’t prevent copying, but it deters illegal copying by providing a means of establishing the ownership of a redistributed copy [8]. A watermark can be applied to any relational database having attributes which changes in their values will not affect the applications [1]. Databases have different types of attributes like, numeric, text, “date and time”, etc. The proposed scheme applied for non-numeric attributes to preserve the value of attributes in database. Generally, database watermarking techniques consists of two main phases: watermark insertion and watermark detection as shown in figure 1 and figure 2. This paper is organized as follow: in section 2; related work is presented, in section 3; overview and flow charts of proposed technique is described in details, in section 4; some important features of the proposed scheme related to security, transfer rate, blind detection and query preserving watermark are discussed, in section 5; analysis and the performance of the proposed system are evaluated with reference to different attacks and in Section 6; conclusion and future work. Figure 1: Digital watermarking –insertion Figure 2: Digital watermarking –detection 2. RELATED WORK Shah et al. [3], suggested a scheme to embed watermark in the alphabetic data attributes. This method is applicable to all the languages with upper/lower character cases. The main advantage of this technique is that it doesn’t affect the semantic meaning of data if the case is changed from small to capital or vice versa. So the query result doesn’t change. Ali et al. [4], proposed technique based on using binary image to watermark the relational database. The bits of the image are segmented into short strings that are encoded in non-numeric, multi-word attributes of selected tuples of the database. A major advantage of using the space-based watermarking is the large bit-capacity available for hiding the watermark. Rajneesh et al. [5], proposed a secure method which uses both semantic and syntactic techniques to watermark the tuple in a relation. The Watermarking technique is dependent on secret key and on the relation. The proposed algorithm is based on the concept of predefined signals of ASCII characters. A secret key is generated by using these signals only. To embed a watermark they used the concept of abbreviations for words and also one of syntactic approach.