Efficient Group Key Establishing Scheme with Resource-and-Location-Aware

Time efficiency in key establishment and rekeying is one of the major problems contributory key managements strive to address. Most schemes which have been put forward improved time efficiency of contributory key management, but they did not consider the scenario where users have varying costs and capabilities. Although conference key tree based on Huffman coding has been proposed to obtain minimum total cost on key establishment considering users computation differences, it did not take communication cost into account. We propose a location-based Huffman (L-Huffman) scheme to minimize the longest key generation time, which is the dominative factor of the group key establishment time. L-Huffman scheme separates users into subgroups according to users' locations and lets the combined users locate in a higher place of the key tree in each subgroup. Simulations demonstrate that L-Huffman has much better performance than Huffman in wide-area networks and is slightly better in local-area networks.