Image integrity and authenticity verification via content-based watermarks and a public key cryptosystem

First, on the transmitting side a binary feature map is extracted as watermark and partitioned into blocks. Secondly, to create a watermarked image, neighboring feature map/watermark blocks are blended and encrypted for insertion.

On the receiving side, the feature map from the received image is extracted again and compared against the recovered watermark to verify the integrity and authenticity. In addition to the capability of detecting geometric transformation, removal of original objects and addition of foreign objects, the proposed scheme is also capable of localizing tampering and detecting cropping without a priori knowledge about the image.