TOWARDS STUDYING THE WLAN SECURITY ISSUES SUMMARY SUBMITTED TO THE KUMAUN UNIVERSITY, NAINITAL BY MANOJ CHANDRA LOHANI FOR THE AWARD OF THE DEGREE OF DOCTOR OF PHILOSOPHY IN COMPUTER SCIENCE UNDER THE SUPERVISION OF Dr. DURGESH PANT PROFESSOR AND HEAD, DEPARTMENT OF COMPUTER SCIENCE, S.S.J. CAMPUS, ALMORA, KUMAUN UNIVERSITY, NAINITAL, UTTARAKHAND (INDIA) 2009
A LAN that employs radio frequency (RF) or perhaps infrared (IR) transmission rather than a wired technology such as coaxial cable, twisted pair, or optical fiber is known as WLAN. A typical WLAN comprises fixed-location transceivers known as access points (APs) to which client workstations and peripherals connect via RF technology. The access points typically are hard wired to switches and routers that interconnect them and provide access to servers. The APs are fitted with radio transceivers and omni-directional antennas. The APs are located at central points where there is good line of sight (LOS) to the workstations and link quality. Most WLANs are standards-based versions from the IEEE 802.11 Working Group. At the Physical Layer the RF specifications include both direct sequence spread spectrum (DSSS) and frequency hopping spread spectrum (FHSS). At the Data Link Layer, the medium access control (MAC) protocol is carrier sense multiple access with collision avoidance (CSMA/CA). Most WLANs operate in the 2.4 GHz unlicensed ISM (Industrial, Scientific, and Medical) band, which avoids the expensive and lengthy licensing process, but carries with it the potential for interference from other systems in proximity. As power levels are low, distances generally are limited to 500 ft circumference. Wireless technologies can be differentiated by the following criteria: Protocol: ATM (Asynchronous Transfer Mode) or IP (Internet Protocol) Connection type: Point-to-Point (P2P) or multipoint (P2MP) connections Spectrum: Licensed or unlicensed The different wireless technologies are as follows:
Broadband Narrowband WAN WAN and WLAN Licensed Unlicensed Digital Analog Line-of-site Non-line-of-site Simplex Half-/full-Duplex Point-to-point Multipoint Broadband Data rates that exceed 1.5 Mbps Licensed Granted by or purchased from the FCC Line-of-site Direct line of site between two antennae Simplex One transmitter The concept of wireless LAN was first introduced in 1980 there after many companies tried to implement variety of wireless LAN applications using spread spectrum, infrared and wideband radio technologies. In 1997, IEEE 802.11 standard provided a solid platform for new applications. The chips supporting IEEE 802.11 standards are already in the market.
The current wireless LAN standards offer very unsatisfactory level of security so the main objective of our work is to suggest appropriate logical modifications in these networks as well as focusing key management issues, authorization techniques and integrity of these systems and developing or modifying the security protocols currently used. The study has been dealt with taking six chapters in all. The first chapter, Introduction, provides the need of study of WLAN security; where and why the WLANs should be deployed. It also clears the scope and limitations of present work done. We have not considered the design issues and these issues are beyond the scope of the present study. However, the modifications in existing protocols are suggested. The second chapter, Wireless Local Area Networks at Glance, provides the glimpses of scope and future of WLANs and the range of existing WLANs. Different IEEE standards are also given proper space in this chapter. All the three WLANs generations are given space. Their deployment issues are mentioned. Different IEEE 802.11 standards are compared. Their merits and demerits are described. The WLAN topologies are duly explained. WLAN technologies such as infrared, UHF and different radio frequencies are given space. Spread spectrum and frequency hopping are also described. The third chapter, The IEEE 802.11 Architecture, is dealt with the architecture of 802.11 WLANs along with different WLAN topologies. Overview of services, such as
distribution of messages, access and confidentiality control services, relationship between services is provided. The fourth chapter, Security Paradigms of WLANs, deals with security paradigms of WLANs. This chapter includes security protocols and the major threats to WLANs. Different security protocols, such as, WEP and WPA are explained. The various types of threats to WLANs are described. The possible drawbacks of IEEE 802.11i are given. Possible modifications are provided in the fifth chapter Suggestive Modifications in Existing Security Protocols. Prevalent Security methods are analyzed and solutions are given. Some other future solutions like quantum cryptographic methods and biometrics are given place in the chapter. A new concept of incorporating biometric authentication in Pre-RSNA phase and quantum cryptography in four way handshaking in RSNA key establishment and management is floated. Biometric authentication of end user will make security more robust and fool-proof. Different types of adversary attacks, such as reflection attack and DoS, can be avoided by applying quantum cryptography in RSNA phase by generating the keys. The last chapter, i.e., sixth one, Conclusion and Summary, concludes the topic, summarizes the work done and provides the guidelines to the future researchers.