Improving Content Authentication Efficiency of Online Multimedia Service

Content authentication is a critical issue for online multimedia systems. A new content authentication scheme based on optimal binary search tree (OBST) was proposed and evaluated to reduce the authentication cost. A balanced tree based approach, however, can not achieve optimal authentication cost when each element is accessed with different probabilities, so it's not appropriate for a practical online multimedia system in which access of the contents is expected to obey Zipf's law. We prove that an OBST based scheme achieves minimized expected authentication cost; we also compare the authentication cost of our scheme to that of a binary search tree (BST) and a red-black tree.