Centralized Key Management and Distribution for Dynamic Multicast Groups: Scalabilility Issues

摘要

We present our work on efficient scalable solutions to the hierarchicalkey management and distribution problem for secure multicast sessions.We take two rooted-tree based schemes that solve hierarchical keymanagement and distribution problem and then present ways of makingthese schemes more efficient by reducing the tree center key storagewith an upper bound on key update communication. The objective ofimproving efficiency is posed as a constrained optimization problem,which we further reduce to a fixed-point equation and find solutions.We also provide a tree design algorithm, which allows the designer tospecify an upper key update communication bound and construct anefficient tree with minimal center storage while maintaining pre-existing logarithmic scalability in time and space requirements. Thechoice of update communication bound as a design factor is the recentdevelopment of multicast communication applications, which have energyor bandwidth as constraints, and these in turn being directly relatedto communication bounds.