International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395 -0056 Volume: 04 Issue: 06 | June -2017 www.irjet.net p-ISSN: 2395-0072 © 2017, IRJET | Impact Factor value: 5.181 | ISO 9001:2008 Certified Journal | Page 2962 Encryption of Decomposed Image by using ASCII Code based Carrier Signal Reema Dhiman 1 , Butta Singh 2 1 Student Mtech, Department of Electronics and Communication Engineering, GNDU RC, Jalandhar, India. 2 Assistant Professor, Department of Electronics and Communication Engineering, GNDU RC, Jalandhar, India. ---------------------------------------------------------------------***--------------------------------------------------------------------- Abstract - Encryption is one of the best method to secure picture data. An ASCII code based carrier signal and image decomposition has been outlined in this paper. Image decomposition is an efficient technique which is used for image encryption and this decomposed image is further proceeding for encryption process. The Carrier image is used for encryption process which is to be generated by using ASCII Codes. A sturdy password is used to encrypt the image with the help of carrier. This method is applied on various images for the calculation of image parameters. After evaluating all these aspects, parameters like correlation, entropy is calculated for both the encrypted as well as decrypted image. Key Words: Carrier Image, ASCII Code, Entropy, Correlation 1. INTRODUCTION Security issues [1] have turned out to be increasingly genuine with the fast improvement of the web and the approach of advanced cell phones that use a lot of private data, particularly pictures, which are presented to the system. However, because of data size and the high excess among the crude pixels of a computerized picture, conventional encryption algorithms such as data encryption standard (DES), international data encryption algorithm (IDEA) and advanced encryption standard (AES) might not be appropriate for image encryption. To forestall image data spillage, many new image encryption algorithms have been proposed by using different techniques, including chaos theory [2], DNA coding [3], and compressed sensing [4]. Information security is one of the significant issues in the current information age, as there is a continuous development in the pace at which the information is being distributed [5]. There are few techniques for image encryption which manages their own thoughts or ideas. In couple of algorithms, encryption process depends just on the catch phrases; however in some different algorithms they utilize some carrier image for encryption. Because of this, we have a thought to combine the current algorithms to get another way for encryption by taking the benefits of individual techniques. Consequently we concoct the idea of decompose the original image and create carrier for Image encryption to get profoundly contorted Image. Panduranga et al proposed [6] a secure method by hybridizing the SCAN pattern and the carrier image for image encryption to get extremely distorted image. They developed the perception of generating the carrier image with the help of distinctive code called as 4 out of 8-code. The proposed hybrid approach for image encryption gives very superior results but the password used in this algorithm is not secure. So, in our proposed approach, ASCII codes are used for generating the carrier image and this carrier is used further for encryption process. 2. PROPOSED METHODOLOGY Encryption of an image should be possible at various stages and in numerous ways. If the encryption process is only in single stage then security is less as contrast with multistage encryption [6]. In our proposed mechanism, the decomposition of image is carried out over various levels and this decomposed image is used for encryption process. Now, the following steps are used for both the encryption and decryption process. 2.1 Encryption Process The encryption process is implemented in MATLAB and it involves the following steps: Step 1: Load an image for encryption. Step 2: Decompose the image into various levels in vertical and horizontal direction. This decomposition is carried out at 4 levels. Step 3: Enter the prototype for arranging the decomposed blocks at level 1, level 2, level 3 and level 4 as shown in Fig-1. Step 4: Enter the password for encryption and generate the carrier image by using ASCII code. The password used in the encryption process is '!~ "z#y$x $w%v &u*t+s,r-q.p/o 1n 2m 3l4k 5j 6i 7h8g 9f:e;d <c=b>a?`@_A^B\CZDY EX FWGV HU ITJS KR LQMP NO'. With the help of this password, a carrier image is generated. Step 5: Add the carrier image with the decomposed image as shown in Fig-2. Step 6: Finally, we get an encrypted image.