• Journal of Digital Convergence
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• v.10 no.6
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• pp.247-251
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• 2012

Tree-based Group Diffie-Hellman (TGDH) is one of the efficient group key agreement protocols to generate the GK. TGDH assumes all members have an equal computing power. As one of the characteristics of distributed computing is heterogeneity, the member can be at a workstation, a laptop or even a mobile computer. Therefore, the group member sequence should be reordered in terms of the member's computing power to improve performance. This research proposes a reordering of members in the group key generation tree to enhance the efficiency of the group key generation.

• Journal of Convergence Society for SMB
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• v.4 no.4
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• pp.19-23
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• 2014

Group communication is becoming increasingly popular in Internet applications such as videoconferences, online chatting programs, games, and gambling. For secure communications, the integrity of messages, member authentication, and confidentiality must be provided among group members. To maintain message integrity, all group members use the Group Key (GK) for encrypting and decrypting messages while providing enough security to protect against passive attacks. Tree-based Group Diffie-Hellman (TGDH) is an efficient group key agreement protocol to generate the GK. TGDH assumes all members have an equal computing power. One of the characteristics of distributed computing and grid environments is heterogeneity; the member can be at a workstation, a laptop or even a mobile computer. Member reordering in the TDGH protocol could potentially lead to an improved protocol; such reordering should capture the heterogeneity of the network as well as latency. This research investigates dynamic reordering mechanisms to consider not only the overhead involved but also the scalability of the proposed protocol.

• Journal of Korea Multimedia Society
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• v.8 no.4
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• pp.525-535
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• 2005

A password-based authenticated tripartite key exchange protocol based on A. Joux's protocol was proposed. By using encryption scheme with shared password, we can resolve man-in-the-middle attack and lack of authentication problems. We also suggested a scheme to avoid the offline dictionary attack to which symmetric encryption schemes are vulnerable. The proposed protocol does not require a trusted party which is required in certificate or identity based authentication schemes. Therefore in a ad hoc network which is difficult to install network infrastructure, the proposed protocol would be very useful. The proposed protocol is more efficient in computation aspect than any existing password-based authenticated tripartite key exchange protocols. When it is used as a base line protocol of tree based group key exchange protocol, the computational weak points of the proposed protocol are compensated.