Abstract: With the presence of image editing software and digital cameras, techniques for digital image tampering are becoming more and more sophisticated and widespread. How to prove the integrity and authenticity of digital images becomes a more and more urgent problem at present, especially in some critical applications, such as court evidence, news broadcast photos, medical images, defence photos, sports pictures etc., in which preserving the exact fidelity of the original image is a legal, moral or technical requirement. Copy-move forgery is one of the widely used tampering techniques where one part of an image is copied to some other part of image in with a view to cover a potentially important feature. In this paper an overview of passive image authentication is presented and the different copy move forgery detection techniques are reviewed.

Keywords: Copy move forgery, Dwt, Dywt, Zernike moment.