| To prevent unauthorized access of multimedia content, effective access control and efficient key management schemes are of crucial importance for multimedia live streaming applications. To address the network heterogeneity, this thesis investigates scalable and multilevel access control, where a single bit stream can offer access to different levels of service. It uses the POSET hash-based structure to explore the data dependency between different layers in scalable coding, and proposes a secure and efficient key management scheme that uses public information and hash functions to reduce the rekey overhead. For those applications that require strict forward/backward security, sequential rekey is used to update keys. This thesis also addresses frequent membership update in live streaming, and considers applications that can tolerate a small amount of content leak. Through exploring their unique characteristics in membership dynamics, the proposed schemes reduce the rekey cost significantly. |
