Realization of a New Robust and Secure Watermarking Technique Using DC Coefficient Modification in Pixel Domain and Chaotic Encryption

1. Introduction

The advancement in communication and networked and multimedia technologies and exponential rise in the users of internet world-wide has resulted in reproduction and distribution of multimedia content likeaudio, images and videos easier. In such a protection of multimedia content has become one of the prominent issues. Various encryption techniques are being used to encrypt the multimedia information before actual data transmission to avert various security and Intellectual Property Right (IPR) problems. However, the disguised look of the scrambled data makes the attacker more suspicious and hence the chances of a malicious attack from the adversary get increased. Given the significance of the problem some serious work needs to be done in order to ensure security and maintain the easy availability of multimedia content. In recent years digital watermarking has received most attention for security and protect multimedia data (Cox et al, 1998; Djurovic et al, 2001; Parah et al, 2014a). A digital watermark is a special data such as logo, imperceptibly embedded in multimedia content like an image etc. to prove its ownership. Since images are one of the prominent members of multimedia content, most of the developed watermark schemes reported till date use images as cover media (Ghouti, et al, 2006). Depending upon visibility of watermark, watermarking schemes are classified into two classes viz.; visible and invisible techniques. Most generally invisible (imperceptible) watermarking is used for copyright protection. Ina typical imperceptible watermarking technique,the watermark or special information datais embedded inside a cover image in such a way that it is imperceptible. Thus, it does not catch the attention of human visual system and protectsthe cover image from common signal processing and geometric attacks. The aim is to create a watermarked image that looks precisely same to a human eye but ensures ownership claim whenever necessary. Digital watermarking has been successfully validated to be very suitable in identifying thesource; creator, owner and distributor of a digital multimedia object (Shih, 2008).