A Novel Approach for Image Steganography Using Dynamic Substitution and Secret Key

Abstract: - Steganography is a system that hides information in an application cover carrier like image, text, audio, and video. Considerable amount of work has been carried out by different researchers on this subject. Least Significant Bit (LSB) insertion method was more suspicious and low robustness against attacks. The objectives of this study were to analyse various existing system and implement a dynamic substitution based Image Steganography (IS) with a secret key. Our proposed method is more difficult to attack because of message bits are not inserted in to the fixed position. In our method, the message bits are embedded into deeper layer depending on the environment of the host image and a secret key resulting increased robustness. The robustness specially would be increased against those intentional attacks which try to reveal the hidden message. Keywords: - I-security, Steganpgraphy, secret key, secure transmission I. INTRODUCTION It is the study of techniques for hiding the existence of a secondary message in the presence of a primary message. The primary message is referred to as the carrier signal or message; the secondary message is referred to as the payload signal or message. The word steganography is derived from the Greek words ‘stegos’ meaning ‘cover’ and ‘grafia’ meaning ‘writing’ [1] defining it as ‘covered writing'. IS means information hidden exclusively inside an image. The main difference between steganography and cryptography is cryptography hide the content of the message and steganography focuses on keeping the existence of a message secret [2]. If there are more similarities between the cover image and the stego-image, it will be harder for an attacker to find out that the stego-image has important secret data hidden inside it. In recent years, enormous research efforts have been invested in the development of digital IS techniques. In this paper, we have proposed a dynamic approach of substitution in IS where message will be embedded depending on the environment of the host image and a secret key not on the fixed position and also adjust a near bit to improve the quality of the image. It becomes more important as more people join the cyberspace revolution. Privacy and anonymity is a concern for most people on the internet. IS allows for two parties to communicate secretly and covertly. It allows for copyright protection on digital files using the message as a digital watermark. One of the other main uses for image steganography is for the transportation of high-level or top-secret documents between international governments. While it has many legitimate uses, it can also be quite nefarious. It can be used by hackers to send viruses and Trojans to compromise machines, and also by terrorists and other organizations that rely on covert operations to communicate secretly and safely. Military communications system make increasing use of traffic security technique which, rather than merely concealing the content of a message using encryption, seek to conceal its sender, its receiver or its very existence. Similar techniques are used in some mobile phone systems and schemes proposed for digital elections. So we prepare and implement it for efficient and secured information transformation. The objectives of the study are to analyse various existing system and implement a dynamic substitution based image steganography with a secret key. This paper has been organized as literature review, proposed work, experiment result following by discussion and conclusion.