1. INTRODUCTIONToday, security is a priority for wireless networks to ensure secure communications. In IEEE 802.16, security was considered the main issue when designing the protocol [1]. The initial network entry procedure in an IEEE 802.16 (WiMAX) network has security flaws that can be exploited by the Man-in-the-Middle (MITM) attack [2]. Improving network security in an active enterprise network with a large number of geographically dispersed subscribers should be done with minimal downtime, so as not to impact critical user data/voice services. The management channel should also be heavily protected to prevent intrusions into the core of the network which contains all servers vital to the functionality of the network. Authentication is the process of validating a user's identity and often includes validation of the services a user can access and, typically involves a supplicant (who resides in the mobile station), an authenticator (who may reside in the mobile station base or in a gateway) and an authentication server [3]. EAP (Extensible Authentication Protocol) is a standard protocol (frequently used in wireless networks) for authenticating data transmission, which is invoked by an 802.1X-enabled Network Access Server (NAS) device such as an 802.11 wireless access point to/ b/g [ 4]. The EAP working group is developing algorithms to support many authentications such as ID/Passwords, certificates, SMART Cards, and session key standardization methods using such authentication algorithms [5]. EAP (see figure 1) integrates different authentication methods (recommended by IEEE) to adapt to the nature of the communication channel, such as EAP-PKM, EAP-MD5, EAP-OTP, EAP-GTC, EAP-TLS, EAP-SIM, EAP-AKA, and also...... middle of paper ......and for Fixed Broadband Wireless Access Systems”, IEEE Press, 2004.[14] IEEE 802.16-2005, "IEEE Standard for Local and Metropolitan Area Networks - Part 16: Air Interface for Fixed and Mobile Broadband Wireless Access Systems," IEEE Press, 2005.[15] P. Rengaraju, L. Chung-Horng, Q. Yi and A. Srinivasan, “Analysis on mobile WiMAX security”, IEEE TIC-STH 2009, Information Assurance in Security and Privacy, Toronto, 2009.[16] K. Scarfone, C. Tibbs, and M. Sexton, “Guide to Securing WiMAX Wireless Communications,” Special Publication of the National Institute of Standards and Technology, pp. 800–127, 2010.[17] R. Dantu, G. Clothier, and A. Atri, “EAP methods for wireless networks,” Computer Standards and Interfaces, vol. 29, pp. 289-301, 2007.[18] C. T. Huang and J. M. Chang, “Answering Security Issues in WiMAX Networks,” IT Professional, vol. 10, number 5, pp.15 -21, 2008.