A Fragile Watermarking Scheme for Authentication of GIF Images

Fragile image watermarking could be used to authenticate a digital image due to modification or altering. A watermark is embedded into the image. When the image was modified or altered, the watermark is also altered or fragile. One of popular image format is GIF image. Some fragile watermarking algorithms are applied to the single GIF image only, none for animated images. However, we could modify the existing steganography algorithm to build a fragile watermarking scheme for any kind of GIF images (still images or animated images). In this paper, we reused EzStego to embed a watermark into the GIF images. EzStego is a steganography algorithm especially for hiding the message in the palette images such as the GIF images. The watermark, which is a binary image, is inserted into a GIF image based on EzStego embeddeing scheme. For increasing security, the watermark is encrypted with the random bits based on chaos system before embedding. To prove authentication of the image, the watermark is extracted from the watermarked image based on EzStego extraction scheme and then compare it with the original watermark. The fragile watermark indicates that the image has been altered. We also could find parts of the image that has been altered. We have tested the performance of the proposed scheme by doing some typical attacks to the watermarked images. Based on experiments results we conclude that the watermarking scheme can detect the authentication of the watermarked images due to the attacks.