WiMAX is a technology that provides continuous high data throughput with low delays for various user types and modes of operation. The security protocols proposed for WiMAX impose a heavy performance overhead, especially on mobile subscribers running real time applications, such as VoIP and IPTV. We propose a hybrid security framework for WiMAX combining Hierarchical Identity-Based Cryptography (HIBC) and certificate based approaches to achieve lower bandwidth usage and higher reliability for stationary as well as mobile subscribers. Our security architecture efficiently resolves the performance issues existing with the current WiMAX security standards and can perform fast handovers. Our framework provides upto a 87% improvement in bandwidth compared to WiMAX's current security standard.