This paper introduces approximate image message authentication codes (IMACs) for soft image authentication. The proposed approximate IMAC survives small to moderate image compression and it is capable of detecting and locating tampering. Techniques such as block averaging and smoothing, parallel approximate message authentication code (AMAC) computation, and image histogram enhancement are used...

We present image data hiding and authentication schemes based on halftoning and coordinate projection. The proposed data hiding scheme can embed images of the same size and similar bit depth into the cover image and robustness against compression is demonstrated. The image authentication scheme is based on the data hiding scheme and can detect, localize, and repair the tampered area of the imag...

Authentication watermarking is a hidden data inserted into an image, in order to detect any alterations. It seems to be almost impossible to design a really secure authentication watermarking without making use of the solid cryptography theory and techniques. In a cryptography-based authentication watermarking, a message authentication code (or digital signature) of the whole image is computed ...