Reduction in control overhead for a secure, scalable framework for mobile multicast

Security in multicast is a necessity for applications that require a group of members to transmit data among themselves. Non-members should be precluded from receiving and sending message to the group. The issue of efficient and scalable key management in such a multicast environment is difficult, since multicast usually involves a large number of hosts. A single change in the group membership often affects many hosts. IOLUS is one existing framework having a central group security controller (GSC) with trusted group security intermediaries (GSI) connected to it. GSIs handle the multicast members. But, IOLUS involves a large overhead whenever a member connected to the GSI leaves the group, since the GSI has to update the sub-group key for all the remaining members. Mobility increases the overhead. In this paper, we introduce micro-grouped IOLUS (M-IOLUS), a novel concept of dynamic micro-groups maintained by the GSI. A ´micro-key´ is used for the transmission of control information. This drastically reduces the control overhead incurred. We have performed extensive simulations varying the different parameters involved and observed a considerable reduction in overhead.