WiMax was designed to provide Broadband Wireless Connectivity over large distances. Security was one of the important considerations while designing this protocol especially after the debacle of the 802.11 series of protocols. However, was this belief and optimism regarding the improved security of this new standard warranted? We believe not and show that this standard is still vulnerable to Denial of Service attacks due to some design issues which have rendered this standard exposed. This research work focuses on identifying the Denial of Service attacks that the 802.16 protocol suite could be vulnerable to and making recommendations to mitigate the risks. Thereafter, we assume that one of the recommendations (encryption of all packets) is implemented and try to see if that makes the protocol robust against denial of service attacks. Interestingly, we find that encryption does not completely secure a protocol against such attacks. This forms the second section of this thesis and is investigated in some detail. Effectively, this work looks into two areas "Denial of Service Vulnerabilities in the 802.16 protocol suite" and "Investigation of the use of side-channel information such as packet size, direction, inter-arrival time and power level to classify encrypted traffic with the aim of constructing efficient denial of service attacks"