Technological development in digital world has led to a huge increase in the popularity of digital images in all domains of life. However, sophisticated and easy to use photo editing software tools have made manipulation of images very easy. Thus there is a need to authenticate images especially in legal matters. The field of image authentication and forgery detection has gained huge popularity lately. A key domain in this regard is copy-move forgery detection. Copy move forgery involves copying a portion of an image and pasting it to a different location in same image, with a purpose to conceal facts. In this paper we attempt to review recent developments in the field of copy move detection. This paper dwells on the detection of copy move forgery based on block based and key point methods, and give a detailed comparison of the state of art techniques.
