Security Analysis of Hash Based Fragile Watermarking Scheme for Image Integrity
N. R. Neena Raj, R. Shreelekshmi · 2019
In this paper, we analyze the security vulnerabilities of hash based fragile watermarking method for image integrity proposed by Gul and Ozturk. The scheme divides the image into non-overlapping blocks of size 32 × 32 which is further subdivided into four sub-blocks of size 16 × 16. A 256 bit watermark generated using SHA-256 from first three sub-blocks is hidden into the fourth sub-block. Tampered blocks are identified by comparing extracted hash with computed hash value. We observe that this scheme is vulnerable to the modification of fourth subblock, swapping of image blocks, cropping attack, collage attack and vector quantization attack.