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| PSA: An Efficient Group Key Updating Algorithm in Secure Multicast |
| Liu Xiao-hu①②; Gu Nai-jie①②; Lu Yu-Liang③; Bi Kun①② |
| ①Dept. of Computer Science & Technology, University of Science and Technology of China, Hefei 230027, China;②Anhui Province Key Laboratory of Computing and Communication Software, Hefei 230027, China;③Teaching and Research Office of Network Engineering, Electronic Engineering Institute of PLA, Hefei 230037, China |
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Abstract Secure multicast uses a group key shared by all group members to encrypt group communication. To ensure security, key server should update the group key (rekey) when an existing member leaves the group or a new member joins the group. Key tree approach is widely used to achieve logarithmic rekeying cost, but the key tree structure has to be kept balanced, otherwise the communication cost in the worst cast will be O(n). In this article a new algorithm named PSA (Path Shuffling Algorithm) is proposed based on key tree. PSA can scatter the balanced operations in normal rekeying operations, so it reduces the restructuring cost and thus improves the performance. Theoretical analysis gives the average updating cost, and experiments show that PSA algorithm has better average-case rekeying performance than other group key updating algorithms.
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Received: 06 March 2006
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2007, Vol. 29 
