94 Volume-4, Issue-4, August-2014, ISSN No.: 2250-0758 International Journal of Engineering and Management Research Available at: www.ijemr.net Page Number: 94-97 Key Based Image Steganography using Dwt and Chaotic Map Shikha Choudhary 1 , Chaten Panwar 2 1,2 M.Tech (IT), Assistant Professor, Shobhit University, Meerut, Uttar Pradesh, INDIA ABSTRACT Steganography is used to increase the security of message sent over the network. Steganography is a Greek origin word which means “hidden writing”. Steganography can be divided into two words Steganos which means “secret” and graphic means “writing”. Image Steganography has been widely studied by researchers. A Steganography technique that uses image as a cover media is called an image Steganography. This paper mainly focuses on key based image Steganography using DWT (discrete wavelet transformation) and chaotic map. In this, the major focus on the secrecy and privacy of information. DWT is used to perform on a grey level cover image for secrecy and on the other hand chaotic map is applied on the secret image for privacy. DWT is used to transform cover image from spatial domain into frequency domain. Transformation can be applied over the entire image to block throughout the image. With the help of this technique we can hide the text within an image and hiding the image within an image and also recover that text and image. Keywords---DWT, Security, Information Hiding, Steganography. I. INTRODUCTION Since the rise of internet is increasing day by day, the most important factor is secret information and communication. Message transmission over the internet still has all kinds of security problems .Cryptography is a way for securing the secret message. Many different methods have been developed for encrypted and decrypted the data in order to keep the message consistence. Sometimes, it is not enough to keep the consistence of message, but also it is necessary to keep the existence of message. Steganography is the technique to implement for this. Steganography means to hide something i.e. information . It is similar to the Watermakingy and Crypography. Watermaking ensures message integrity, Cryptography scrambles a message, so it cannot be understood and Steganography hides the message. Steganography provides a means of communicating a secret message. So an unauthorized user cannot understand the existence of the message. Encryption and Steganography have the same goal but different means. Encryption encodes the data such that an unauthorized person cannot get the useful meaning but Steganography prevent the data from an unauthorized receiver that he will not be inspects data is there. It allow for a better private communication. The main work of Steganography is to replace bits of useless or unused data in regular computer files (such as graphics, sound, text) with the bits of different invisible information. This hidden information can be plaintext either cipher text or even image. When encryption is not permitted, Steganography can be used. One more common Steganography can be used for supplement encryption, with the help of Steganography an encrypted file may still hide the information .. The word Steganography is derived from the Greek word stenos Means “cover” and graphia means writing defined as “covered writing”. The technique has been used in ancient time where secret message were tattoos on the shaven heads of the messengers . These messengers were sent away after their hair grew up and were later shaved again to recover the messages. The main goal of Steganography is to hide the information from an unauthorized person. The hidden information may be plain text, cipher text or image or anything that can be embedded into bit stream. In another aspect Steganalysis is a way of detecting possible secret communication using against Steganography. The advantage of the Steganography is that it can be used to transmit the secret message. This paper mainly focus on DWT algorithm and Chaotic Map used for image Steganography and also discuss the various types of Steganography techniques. Nowadays multimedia contents like Audio, Video, and Images are also transferring across a network. A digital image has also across a network to be transferred frequently. As per this transferring needs security because of some military, medical images, cable TV are payable. So there is a need of technique that can provide security to these digital images. Hence, image Steganography is used to provide this facility to these images. Image Steganography hides the secret image into a cover image. So that only reliable and authorized user can get it. Unauthorized user cannot get it [3, 4]. A. STEGANOGRAPHY Vs. CRYPTOGRAPHY Basically the purpose of Cryptography and Steganography is to provide secret communication. However Steganography is different from Cryptography. Cryptography hides the contents of secret message while
Key Based Image Steganography using Dwt and Chaotic …€¦ · focuses on key based image Steganography using ... Fig.1 Steganography Techniques (a) Text-Based Steganography ...