On a new approach of insertion of confidential digital signature into images

In past few years, with the development of telecommunication systems and new multimedia services, the protection of digitally stored information has become an urgent problem. The introduction of a code or watermark into image data (signing the image) is a satisfying technical solution to digital still image protection. This invisible watermark should allow determination of the owner of the image without increasing the quantity of the initial digital information. It should also maintain the visual quality and be difficult to detect and remove. In this study, we propose a new approach to signing digital images based on the slight modification of a limited number of AC coefficients of the discrete cosine transform (DCT).