Digital Image Watermarking for Copyright Protection Shankar Thawkar Department of Information Technology Hindustan College of Science and Technology, Mathura (UP), India Abstract— Digital Watermarking is the process of embedding data called watermark or signature or label or tag into a multimedia object (image or audio or video) so that the watermark can be extracted for ownership verification or authentication. A visible watermark is a secondary translucent image overlaid into the primary image and appears visible to a viewer on a careful inspection. The invisible watermark is embedded in such a way that the modifications made to the pixel value is perceptually not noticed and it can be recovered only with an appropriate decoding mechanism This paper presents an invisible image watermarking scheme for copyright protection and temper detection. The secret key encryption algorithm is used for embedding the watermark using LSB technique. The verification (the watermark extraction) process uses the same key as in encryption, and hence it can be used for copyright protection of digital media such as images, audio and video. The proposed method able to detect any modification made in the image pixels. Keywords— Digital Watermarking, Secret key, Encryption, Decryption, Least Significant Bit. I. INTRODUCTION Digital Watermarking is the process of embedding data called watermark or signature or label or tag into a multimedia object (image or audio or video) so that the watermark can be extracted for ownership verification or authentication. This technology is becoming important due to the popularity of usages of images on web. In general any watermarking algorithm consist of three parts [1]-  Watermark  The encoder  The decoder Watermarking techniques can be divided into various categories in various ways [1]. Watermarking techniques can be divided into four categories according to the type of document to be watermarked as follows:  Text Watermarking  Image Watermarking  ·Audio Watermarking  Video Watermarking In other way, the digital watermarks can be divided into three different types as follows:  Visible watermark  Invisible-Robust watermark  Invisible-Fragile watermark In Visible watermarking watermark appears visible to a casual viewer on a careful inspection. The invisible-robust watermark is embedded in such a way that alternations made to the pixel value are perceptually not noticed and it can be recovered only with appropriate decoding mechanism. The invisible-fragile watermark is embedded in such a way that any manipulation or modification of the image would alter or destroy the watermark. In this paper we used invisible watermarking. The watermark is encoded using secrete Key so that the ownership of the images can be verified using the same key. In such a system, the owner of the image inserts a watermark using a secret key K. In the watermark extraction procedure, the owner uses the same key [3] to prove ownership of the object. This technique is very useful for copyright protection, and it prevent illegal use of the multimedia content without the prior permission of owner. The proposed scheme is also capable of detecting any changes made in the pixel values of the image, this is achieved by inserting the image hash along with the encrypted message digest in the image. The rest of the paper is organised as follows : In section 2 the proposed scheme is described in detail ; experimental results are presented in section 3 and conclusions are drawn in section 4. II. PROPOSED SCHME The basic idea of proposed scheme is to provide Image Integrity and Copyright protection which uses cryptographic functions such as encryption for copyright protection and hash function for Image Integrity. The working of the proposed scheme involve following steps- A. Watermark Embedding Algorithm The watermark embedding process is stated in the following algorithm- Shankar Thawkar / (IJCSIT) International Journal of Computer Science and Information Technologies, Vol. 3 (2) , 2012,3757-3760 3757