Hamming code and logistic-map based pixel-level active forgery detection scheme using fragile watermarking

In this work, an active forgery detection scheme is proposed to locate the tampered region from a forged digital image. In this regard, an authentication code is formed and subsequently, the same is concealed into each pixel for the realization of a fragile watermarked image. In an active forgery detection procedure, the extracted authentication code from the fragile watermarked image is considered to detect the tampered region properly. The main goal of this work is to generate a secure authentication code for preventing the attackers from purposely altering the embedded code to match the tampered image contents as well as to cause less visual distortion after the construction of the fragile watermarked image. Initially, the authentication code for each pixel is computed using Hamming code from the first four most significant bits (MSBs) and subsequently, the same is considered to conceal into some least significant bits (LSBs) of that particular pixel. Generally, the LSB components are found visually insignificant so, the suggested pixel-level authentication code embedding procedure retains the high visual quality of the watermarked image. The proposed fragile watermarking is secured since the authentication code embedding procedure is realized using the logistic-map based generated secret parameters. The proposed scheme has been implemented and the results based on the input of several grayscale images are found satisfactory. In addition, several tampered images are considered to validate the proficiency of tampering detection of the proposed work. The obtained results demonstrate that the presented work is effectively capable to detect the tampered region even in pixel-level from the forged digital image content and also the results are found comparable to some related works.