Enhanced Diffusion Encryption for Video Transmission over Mobile WiMax Networks M.A. Mohamed, F.W. Zaki and A.M. El-Mohandes Electronics and Communication Engineering, Faculty of Engineering-Mansoura University Mansoura, Dakhlia, Egypt mazim12@yahoo.com, fwzaki@yahoo.com and awny11_9@yahoo.com Abstract As a promising broadband wireless technology, WiMax has many salient advantages over such as: high data rates, quality of service, scalability, security, and mobility. Many sophisticated authentication and encryption techniques have been embedded into WiMax but it still exposes to various attacks in. In this paper, three proposed chaos encryption techniques were described for video transmission over Mobile WiMax as an enhancement of multimedia security problem in Mobile WiMax which use AES algorithm. At first, a global overview of the technology WiMax was given to determine the disadvantages of recently used encryption algorithm with video transmission. Then the proposed encryption techniques were presented with its chaos systems. Next, these proposed techniques and AES were applied to video to compare between them. It was found that when Henon and Baker maps are combined in one technique, it will have high speed and more robust to statistical and differential attacks, so we can say that this technique enhances the diffusion properties for video encryption. Keywords: IEEE 802.16e, Security Sublayer, AES, Chaos and Encryption. 1. Introduction WiMax, also known as the IEEE 802.16 protocol, is the latest standard for wireless networks. It was established in 1999 to prepare specifications for broadband wireless metropolitan area networks. The first 802.16 standard was approved in December 2001 and was followed by three amendments: 802.16a, 802.16b and 802.16c. In 2004 the 802.16-2004 standard was released and the earlier 802.16 documents including the a/b/c amendments were withdrawn. An amendment to 802.16-2004, IEEE 802.16e-2005, addressing mobility, was concluded in 2005. This implemented a number of enhancements to 802.16-2004, including better support for Quality of Service, Security and the use of Scalable OFDMA, and is sometimes called ―Mobile WiMax‖, after the WIMAX forum [1]. The security sublayer of the IEEE 802.16 standards defines different security mechanisms which support: (i) authenticate the user who enters in to the network, (ii) authorize the user, and then (iii) provide the necessary encryption support for the key transfer and data traffic. The IEEE 802.16 standards security architecture is based on PKM (Privacy Key Management) protocol which provides a flexible solution that supports device and user authentication between a mobile station and the home connectivity service network. Even though this standard brief the medium access control (MAC) and physical (PHY) layer functionality, it mainly concentrate on point- to-multipoint (PMP) networks. In the concern of security, mesh networks are more vulnerable than the PMP network. The goal of the Security Sublayer is to provide the mutual authentication for access control and confidentiality of the data link layer [2]. It has two component protocols: (i) an encapsulation protocol for multimedia encryption and authentication algorithms, (ii) a key management protocol (PKM) providing the secure distribution of keying data from the base station to the mobile station [2]. The security sublayer of Mobile WiMax standard depends on AES to encrypt MAC layer PDUs with different key sizes. According to the properties of video; the AES algorithm appears not to be ideal for the following reasons: (i) Videos are usually very large-sized and bulky, encrypting such bulky data with the traditional ciphers incurs significant overhead and it is too expensive for real-time multimedia applications, (ii) In the case of video frames, adjacent pixels often have similar gray-scale values and strong correlations, and consecutive frames are similar and most likely only few pixels would differ from frame to frame. Such an extremely high data redundancy of video makes the AES fail to obscure all visible information. So in this research AES algorithm are replaced by three proposed algorithms based on chaos systems and compared together to determine features of them such as speed, throughput, resist to statistical and differential attacks on selected frames of video. The rest of the paper is organized as follows: The Mobile WiMax overview is discussed in the next section. Section (3) discusses three new proposed techniques and AES. Section (4) introduces experimental design. Section (5) presents results and discussion. Section (6) is the conclusion. 2. Mobile WiMax: An Overview The IEEE 802.16-2009 standard defines a generic reference model where major functional blocks (i.e., IJCSI International Journal of Computer Science Issues, Vol. 10, Issue 2, No 1, March 2013 ISSN (Print): 1694-0814 | ISSN (Online): 1694-0784 www.IJCSI.org 213 Copyright (c) 2013 International Journal of Computer Science Issues. All Rights Reserved.