International Journal of Science and Research (IJSR) ISSN (Online): 2319-7064 Index Copernicus Value (2013): 6.14 | Impact Factor (2015): 6.391 Volume 5 Issue 10, October 2016 www.ijsr.net Licensed Under Creative Commons Attribution CC BY Arnold’s Cat Map Algorithm in Digital Image Encryption Eko Hariyanto 1 , Robbi Rahim 2 Keyword: Cryptography, Arnold's Cat Map, Digital Image Encryption, Image Cryptography 1. Introduction Computer security is a branch of technology known as information security as applied to computers. Computer security objectives are among others the protection of information against theft or corruption, or the preservation of availability, as outlined in the security policy[1]. Image is one of the important forms of multimedia. Image visually present information and information presented by a richer image than presented textually[2]. Digital images are not only stored in the storage such as hard disks, flash drives, CDs, DVDs, and other storage device, but also transmitted via public channels such as the internet. For the image of the private or confidential, storage and transmission of images need to pay attention to security aspects. The image that is private personal documents such as photos can only be seen by the owners or those who are given authority only [2], confidential example is the image of the remote sensing (satellite photo) recording potential of natural resources of a country[2]. Recently an effective security of a system is needed for daily business activities. A secure system can provide a high level of confidence to the user so that it can add value and efficiency to the system itself. Users will feel comfortable and safe when dealing with a system that can secure user data from attackers. In addition to the image of private and confidential, the security aspect is an important feature in the image paid. Only paid customers who can access the information in the image. A digital video is essentially composed by a series of still image frames are displayed in a very short time. For the industry of multimedia such as Pay TV or video on demand, protection against broadcast video plays an important role, because video broadcasts transmitted by broadcast through the transmission line (which can be intercepted) but only paying customers are able to enjoy live TV, while the illegal subscribers are not can access the video broadcast. Researchers have developed a lot of cryptographic algorithms for encryption, but most algorithms are intended Arnold’s Cat Map algorithm (ACM) is one of the cryptographic algorithm used to encrypt the image [4]The concept of the algorithm is continuously rotate the image so that it becomes a form that is not visible and random so that the image can not be seen by the naked eye but can still be recognized by the system for image file (image) of the same [4]. 2. Arnold’s Cat Map Algorithm Chaos is a common technique used in the random number generator[5], it's happening because this technique is faster and easier to use in the process stream object both in terms of storage and process objects Only a few functions (chaotic maps) and some parameters (inital conditions) were quite good used if the process takes quite a long time [5]. Arnold's Cat Mapare chaotic two dimensions that can be used to change the position of the pixel of the image without removing any information from the image[6], pixel image can be assumed by S = {(x, y) | x, y = 0, 1, 2 ... N-1} . 2- dimensional image of Arnold's Cat Map can be written by the following equation: ( ) n y x A y x mod ' '       =       ( ) n y x pq q p mod 1 1             + Paper ID: ART20162488 DOI: 10.21275/ART20162488 1363 1 Faculty of Computer Science, Universitas Pembangunan Panca Budi, Jl. Jend. GatotSubroto Km. 4,5SeiSikambing, 20122, Medan, Sumatera Utara, Indonesia 2 Faculty of Computer Science, Universitas Pembangunan Panca Budi to encrypt messages in text form. Although conventional encryption algorithms such as DES, AES, Blowfish, Serpent, RC4, RSA, ElGamal, Rabin, can also encrypt images [3], but the algorithm is safe enough to be applied. This is due to the image have different characteristics with textual data. An image generally has a data capacity is very large, so the image encryption requires large computational volume. Some applications that have a need for real-time such as teleconferencing, live video streaming, and others, obviously require very high computing speed that the conventional algorithm is obviously not suitable for encrypting image[3]. Abstract: Cryptography is a field that has developed very rapidly with the number of algorithms that keep popping up with this type of symmetric and asymmetric which has advantages and disadvantages of each, the algorithm Arnold's Cat Map is one type of cryptographic algorithms to secure the digital image by performing iterations for n in the pixel image and the outcome can not be known without knowing the value of a process of iteration