A tamper detection suitable fragile watermarking scheme based on novel payload embedding strategy

Abstract

Intentional tampering in digital image content is one of the common malpractices in the current digital arena. So in this paper, the authors have proposed a novel fragile watermarking scheme for the localization of tampered image content effectively. Proposed fragile watermarking scheme detects forged image content robustly in block level of two consecutive pixels. In this work, the watermark embedding procedure is comprised of two phases- i.e., authentication code generation from some selected salient bits of each pixel of the original image content, and encryption of the authentication code before realizing it for embedding into the insignificant bits of each pixel in the original cover image. The authentication code is computed from each block using Hamming Code. Subsequently, the encrypted code is concealed into the pixels of that particular block using the suggested payload embedding strategy i.e., pixel adjustment process. The proposed fragile watermarking procedure ensures the high level of security since the encrypted authentication code is embedded into the cover image through an indirect mechanism i.e. block-level pixel adjustment process. This scheme has been implemented and tested on several grayscale images in order to confirm the tampering detection capability against various image manipulation attacks. The experimental results exhibit better performance in terms of various perceptual quality measures like peak signal to noise ratio, structural similarity index, and image fidelity. Further, the presented results demonstrate that the scheme is suitable for detecting whether a concerned image has undergone any form of tampering or not and achieves standard results in terms of false-positive rate, false-negative rate, true positive rate, tamper detection accuracy, and normalized cross-correlation.