Lazy Wavelet Transform Based Steganography in Video Khushman Patel, Kul Kauwid Rora, Kamini Singh, Shekhar Verma Dept of CSE, IIIT Allahabad, Allahabad (U.P.) Abstract—Visual steganography is the most widely practiced form of steganography. It started with concealing messages within the lowest bits of noisy images or sound files. We shall perform steganography on video files and hide the message in an encrypted format, thus achieving a multiple cryptographic system. The most commonly used technique is Least Significant Bit steganography (LSB steganography). But instead of traditional LSB encoding, we will use a modified encoding technique which will first transform the video using a Lazy Lifting Wavelet transform and then apply LSB in the sub-bands of the video that has been obtained. The proposed approach to video steganography utilizes the visual as well as the audio component. The lazy wavelet transform is applied to the visual frames, and the data is stored in the coefficients of the visual component. The length up to which it is stored is hidden using LSB in the audio component. Experimental results show that the proposed technique does not affect the higher and lower ends of the frequency distribution of the signal. Moreover, it has a high payload capacity and low computational requirements. Keywords- Steganography; Lazy Wavelet Transform; data embedding; Audio LSB. I. INTRODUCTION Steganography and cryptography are the two main methods for information hiding and security today. Information hiding (steganography) aims at hiding the very existence of the secret message itself [1]. It is done by hiding the secret data in any innocuous medium, so that is it not apparent that there is any data hidden in the cover medium. Cryptography is the technique which scrambles the secret information itself so that it cannot be understood without unscrambling it. A cipher is usually applied in case of cryptography [2]. Multimedia files, such as images, audio and video are widely used today. Images are a good medium for hiding data. The more detailed the image, the lesser constraints there are on how much data it can hold without it becoming conspicuous [3]. There are several tools available for hiding data in audio files, but the large size of meaningful audio files then made it less popular than image files as a steganographic medium. But both these mediums have a lot less storage capacity as compared to videos, since videos can be taken as a collection of frames (images) and audio [5]. Steganography in video files was introduced in [4]. In this paper, we have discussed a new method of steganography along with cryptography which will be applied with videos as the cover medium. There are many cryptography algorithms have been create d which turn the data into unreadable ciphers (an encrypted piece of text). There are two basic methods: symmetric key cryptography and public key cryptography. We will discuss symmetric key cryptography, since we will be using it in our proposed method. Symmetric key cryptography uses a common key for encryption and decryption of the message. This key should be known both to the sender and the receiver. The sender encrypts the data using this key and sends it to the receiver who then decrypts it using this same key to get the original message. These algorithms are less complex and execute faster as compared to other algorithms, but in this case, there is a need to share the key securely between both the sender and the receiver. The security of the data is equal to the security of the key [2]. Multimedia steganography is one of the most recent and secure forms of steganography. Visual steganography is the most widely practiced form of steganography. It started with concealing messages within the lowest bits of noisy images or sound files. We shall perform steganography on video files and hide the message in an encrypted format, thus achieving a multiple cryptographic system. The most commonly used technique is Least Significant Bit steganography (LSB steganography). But instead of traditional LSB encoding, we will use a modified encoding technique which will first transform the video using a Lazy Lifting Wavelet transform and then apply LSB in the sub- bands of the video that we have gotten. The rest of the paper is organized as follows. The visual cryptographic based steganography based technique proposed in the work is described in section II. Section III contains the implementation details. Section IV presents results and discussion. The paper is concluded in section V. II. PRPOSED TECHNIQUE The Visual Cryptographic Steganography Model In this model, we will encrypt the message using the symmetric key algorithm, and after that hide the data into a video file, which will act like our cover. At the receiving side, we will first extract the hidden data from the received video file, and then decrypt it using the shared key that we already know. Hiding Procedure A video file is usually composed of multiple frames [5]. This method uses some frames (or images) of the video to hide the secret message. The secret data is hidden in sequential frames. Each frame is treated as a different image and an image steganography method is applied to them. We use the 2D - Lazy Wavelet Transform on each frame to get four sub-bands. The data is then hidden in these four sub- bands using LSB to hide 3 bits in each element of the sub- band. The length of the data stream which is encoded into 2013 International Conference on Communication Systems and Network Technologies 978-0-7695-4958-3/13 $26.00 © 2013 IEEE DOI 10.1109/CSNT.2013.109 497