A Time-Bound and Hierarchical Key Management Scheme for Secure Multicast Systems

In this paper, we have adopted elliptic curve multiplication operation, ID-based character in bilinear pairing, one-way hash function, and time access control to construct a time-bound hierarchical access control and key management scheme for multicast systems. In this scheme, central authority distributes a group key for every security class (SC) and a time-bound secret key for each member of security class. With its time-bound secret key, each member in SC can obtain a group key to decrypt the message and thereof utilize the group key to attain the group keys for successors so as to decrypt their data sets. Considering many common ways of dynamic access control, namely, a new member joining in the security class, an existing member departing from a security class, replacing time-bound key, increasing security class, decreasing security class, replacing group key, adding relationship and deleting relationship among SCs, all of them are explicitly discussed in this paper. In view of the security and performance analyses under many typical attacks, we thereby prove our proposed scheme can prevent malicious attacks effectively with less computation time and more reasonable complexity. In consequence, the proposed scheme offers a secure and hierarchical access control in multicast systems.