  Content-independent watermarks and block-wise independency can be considered
as vulnerabilities in semi-fragile watermarking methods. In this paper to
achieve the objectives of semi-fragile watermarking techniques, a method is
proposed to not have the mentioned shortcomings. In the proposed method, the
watermark is generated by relying on image content and a key. Furthermore, the
embedding scheme causes the watermarked blocks to become dependent on each
other, using a key. In the embedding phase, the image is partitioned into
non-overlapping blocks. In order to detect and separate the different types of
attacks more precisely, the proposed method embeds three copies of each
watermark bit into LWT coefficients of each 4x4 block. In the authentication
phase, by voting between the extracted bits the error maps are created; these
maps indicate image authenticity and reveal the modified regions. Also, in
order to automate the authentication, the images are classified into four
categories using seven features. Classification accuracy in the experiments is
97.97 percent. It is noted that our experiments demonstrate that the proposed
method is robust against JPEG compression and is competitive with a
state-of-the-art semi-fragile watermarking method, in terms of robustness and
semi-fragility.
