Mobile Multihhop Relay WiMAX network is the enhancement of relays to support Multihop in increasing the wireless coverage, lower backhaul deployment cost, easy setup and high throughput. Security of MMR WiMAX networks for distributed hop-by-hop authentication and localized key management as well as forward and backlward secrecy is the the main challenge. To successfully accomplish the above challenges, this book proposes security protocols fo MMR WiMAX into two security levels: Authentication & Key Management and Multicast & Broadcast Services.