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arXiv · 0904.4061

Approximation Algorithms for Key Management in Secure Multicast

Agnes Chan·Rajmohan Rajaraman·Zhifeng Sun·Feng Zhu
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Abstract

Many data dissemination and publish-subscribe systems that guarantee the privacy and authenticity of the participants rely on symmetric key cryptography. An important problem in such a system is to maintain the shared group key as the group membership changes. We consider the problem of determining a key hierarchy that minimizes the average communication cost of an update, given update frequencies of the group members and an edge-weighted undirected graph that captures routing costs. We first present a polynomial-time approximation scheme for minimizing the average number of multicast messages needed for an update. We next show that when routing costs are considered, the problem is NP-hard even when the underlying routing network is a tree network or even when every group member has the same update frequency. Our main result is a polynomial time constant-factor approximation algorithm for the general case where the routing network is an arbitrary weighted graph and group members have nonuniform update frequencies.

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Agnes Chan, Rajmohan Rajaraman, Zhifeng Sun, Feng Zhu. 2009-04-27. Approximation Algorithms for Key Management in Secure Multicast. https://arxiv.org/abs/0904.4061

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