Color image authentication through a dynamic fragile watermarking framework

Ownership authentication of image attended a careful attention due to global availability of internet services. Illegal copying and misappropriation of digital image leads cyber crime in an epidemic form. In aforesaid regard we´ve already proposed different fragile color image authentication schemes which guarantees ownership of an image through embedding color watermarks into color host images. In present communication we are going to propose a technique which will ensure the ownership authentication in a dynamic manner. The proposed framework will form the watermark from the host image by combining the unique high frequency zone of the host image with the help of a user specific secret key. After that the dynamically formed watermark will be inserted into the host image with our already reported LSB framework. In proposed watermarking framework, it allows a user with an appropriate secret key and a hash function to verify the authencity, integrity and ownership of an image. If a forger performs the watermark extraction with an incorrect key and inappropriate hash function, the user obtains an image that resembles noise. In this manner we are providing an integrated solution for ownership authentication where not only the watermark is unique for that particular host image, but also the overhead to create a separate watermark logo is minimized by the dynamic scheme. Thus the authentication is ensured in an efficient way. At the watermark extraction end, we´ve used blind extraction method, i.e., neither the host image nor the watermark image is required at the time of watermark extraction.