ABSTRACT In this paper, a novel watermarking technique is proposed for data authentication and integrity of Relational Database. For integrity verification of tables in the database, the watermark has to depend on a secret key and on the original copy of that table. It is important that the dependence on the key should be sensitive. The proposed method makes use of the concept of eigen values by constructing a tuple -Relation matrix for each tuple. The eigen values are used for generating the watermark for a record in the table. Watermark embedding is done by using eigen values in a non numeric attribute of a tuple. Detection of the watermark prove the authenticate and integrity of data. We will show that our approach leads to an effective technique that is robust against different forms of malicious attacks as well as benign updates to the data . General Terms Security Keywords Watermarking, Relational Database, Eigen values; 1. INTRODUCTION Digital images, video and audio are examples of digital assets which have become easily accessible by ordinary people around the world. However, the owners of such digital assets have long been concerned with the copyright of their digital products, since copying and distributing digital assets across the Internet was never easier and possible as its now a days. Digital watermarking technology was suggested lately as an effective solution for protecting the copyright of digital assets[2,3]. This technology provides ownership verification of a digital product by inserting imperceptive information into the digital product. Such 'right witness' information is called the watermark and it is inserted in such a way that the usefulness of the product remains, in addition to providing it with robustness against attempts to remove the watermark. A watermarking of database systems started to receive attention because of the increasing use of database systems in many real-life applications. There is a need to preserve originality, ownership and integrity of database systems in a way that cannot be identified by everyone. It in turn arises the need of developing a well secured watermark technique to protect the database systems against the piracies. Many researchers concentrated on watermarking numeric attribute relational database systems and also for non numeric attribute which stores image in it[1,2,6]. In this paper, we present an effective watermarking technique for non numeric relational data that is robust against various attacks. The main contributions of the paper are summarized as follows: We select non numeric low impact attributes which are used to watermark a relation. During watermark generation process, we design an algorithm for : 1. Secret Key generation using Eigen values of tuple-Relation matrix for a tuple. 2. Watermark insertion. 3. Watermark detection is the reverse process of watermark insertion. As any change to non-numeric attribute values of the tuple must be a change in vowel, consonant, numbers and special character of tuple-Relation matrix, we consider their individual counts to compute the weighted ASCII sum A for developing a new watermarking scheme. It provides a secret key to the authenticated user to verify the received database relation. If the database has undergone tampering during transmission, it can be recognized by the authenticated user.