• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.2
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• pp.935-949
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• 2016

In this paper, we present a novel authenticated group key distribution scheme for large and dynamic multicast groups without employing traditional symmetric and asymmetric cryptographic operations. The security of our scheme is mainly based on the basic theories for solving linear equations. In our scheme, a large group is divided into many subgroups, where each subgroup is managed by a subgroup key manager (SGKM) and a group key generation center (GKGC) further manages all SGKMs. The group key is generated by the GKGC and then propagated to all group members through the SGKMs, such that only authorized group members can recover the group key but unauthorized users cannot. In addition, all authorized group members can verify the authenticity of group keys by a public one-way function. The analysis results show that our scheme is secure and efficient, and especially it is very appropriate for secure multicast communications in large and dynamic client-server networks.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.6
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• pp.69-78
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• 2004

During the last decade, security models have been defined for two- and three-parity key exchange protocols. Currently there is a growing research interest in security models for group key management schemes. While various security models and provably secure protocols have been proposed for distributed group key exchange schemes, no results are hewn for centralized group key distribution schemes in spite of their theoretical and practical importance. We describe security requirements and a formal security model for centralized group key distribution scheme: we define the model on the channel controlled by adversaries with the ability of strong user corruption. In the security model, we propose a conversion module which can transform centralized tree-based group key distribution schemes in the literature to provably secure centralized tree-based group key distribution schemes.

• The KIPS Transactions:PartC
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• v.9C no.3
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• pp.331-336
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• 2002

In this paper, we propose a new distribution and renewal scheme for a group key suitable for secure mobile communications based on identification protocol, in which all members of the group can reshare the new group common key except revoked members by using a key distribution center (a trusted center). The security of this scheme is based on the difficulty of the discrete logarithm problem. The proposed scheme can be appropriately managed in case that terminal's capability of storage and computing power is relatively small and more than one caller are revoked. It also renews a group key easily when the center changes this key intervally for security.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.4
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• pp.878-894
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• 2013

Secure multimedia multicast applications involve group communications where group membership requires secured dynamic key generation and updating operations. Such operations usually consume high computation time and therefore designing a key distribution protocol with reduced computation time is necessary for multicast applications. In this paper, we propose a new key distribution protocol that focuses on two aspects. The first one aims at the reduction of computation complexity by performing lesser numbers of multiplication operations using a ternary-tree approach during key updating. Moreover, it aims to optimize the number of multiplication operations by using the existing Karatsuba divide and conquer approach for fast multiplication. The second aspect aims at reducing the amount of information communicated to the group members during the update operations in the key content. The proposed algorithm has been evaluated based on computation and communication complexity and a comparative performance analysis of various key distribution protocols is provided. Moreover, it has been observed that the proposed algorithm reduces the computation and communication time significantly.

• Journal of the Korea Society of Computer and Information
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• v.9 no.3
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• pp.177-182
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• 2004

The existing group key management architectures applied to a small scale routing protocols may have many overheads with key distribution. Therefore this paper proposes a group key management protocol in PIM-SM multicast group communication. This method divide multicast groups with RP, and subgroup key managers are established in each RP and can be transmitted groups keys. And this does not have needs of the data translation and the new key distribution for path change. This does not have needs of the data translation and the new key distribution for path change, so the data transmission time can be reduced.

• Journal of Communications and Networks
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• v.18 no.2
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• pp.246-260
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• 2016

A major challenge achieving scalable access control for a large number of subscribers in a public broadcast is to distribute key update messages reliably to all stateless receivers. However, in a public broadcast, the rekeying messages can be dropped or compromised during transmission over an insecure broadcast channel, or transmitted to receivers while they were off-line. In this study, we propose a novel group key management scheme. It features a mechanism to allow legitimate receivers to recover the current group key, even if they lose key update messages for long-term sessions. The scheme uses short hint messages and member computation. Performance analysis shows that the proposed scheme has the advantages of scalability and efficient rekeying compared to previous reliable group key distribution schemes. The proposed key management scheme targets a conditional access system in a media broadcast in which there is no feedback channel from receivers to the broadcasting station.

• The KIPS Transactions:PartC
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• v.13C no.3 s.106
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• pp.339-344
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• 2006

Secure delivery of multicast data can be achieved with the use of a group key for data encryption in mobile ad hoc network (MANET) applications based on the group communication. However, for the support of dynamic group membership, the group key has to be updated for each member joining/leaving and, consequently, a mechanism distributing an updated group key to members is required. The two major categories of the group key distribution mechanisms proposed for wired networks are the naive and the tree-based approaches. The naive approach is based on unicast, so it is not appropriate for large group communication environment. On the other hand, the tree-based approach is scalable in terms of the group size, but requires the reliable multicast mechanism for the group key distribution. In the sense that the reliable multicast mechanism requires a large amount of computing resources from mobile nodes, the tree-based approach is not desirable for the small-sized MANET environment. Therefore, in this paper, we propose a new key distribution protocol, called the proxy-based key management protocol (PROMPT), which is based on the naive approach in the small-sized MANET environment. PROMPT reduces the message overhead of the naive through the first-hop grouping from a source node and the last-hop grouping from proxy nodes using the characteristics of a wireless channel.

• The KIPS Transactions:PartC
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• v.13C no.7 s.110
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• pp.913-922
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• 2006

It used exclusively the radio communication where is the TRS(Trunked Radio Service) at frequency where the person whom it does is specific with hitherto radio communication method differently frequency of the decimal which is allocated to the relay station it talks the at the room which the multiple user uses with commonness. The TRS system the most big feature is the region multiple group and order communication method. The TRS the composition of system is composed of the multi mind group, the each group is composed of the terminal of the users who have the objective which is similar relates in business contents. With above it follows in same multi objective and the connection of the form which is various or group communication accomplishes and quality case, a possibility a or of having many problem point in key distribution for a large scale communication there is it could be exposed to attack of the form which is various. There is a place where it accomplishes the communication which is safe at the TRS from research which it sees it investigates group key distribution method which is an essential element. The method which it sees when it reduces a communication frequency, it stands but is the user, it proposes the efficient group key distribution method it will be able to accomplish.

• Journal of KIISE:Information Networking
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• v.27 no.1
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• pp.48-57
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• 2000

The need for high bandwidth, very dynamic secure internet multicast communications is increasingly evident in a wide variety of commercial, government, and internet communities. One of the most recently researches is mainly about the group key distribution schemes[1,3,4,5]. In this paper, we survey related group key distribution schemes and propose a new scalable distributed group key distribution scheme which is one of the most important parts in internet multicast environment. Then, we add this scheme to the existing multicast applications and analysis the test results. The proposed SDGD minimizes the times required to distribute and redistribute keys for joining and leaving the multicast group.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.152-156
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• 2001

In this paper we propose a secure multicast key distribution protocol using OFT(One-way Function Trees). The proposed protocol is a hybrid scheme of DKMP(Distributed Key Management Protocol) that guarantees all group member's participation for generating a group key, and CKMP(Centralized Key Management Protocol) that makes it easy to manage group key and design a protocol. Since the proposed protocol also computes group key using only hash function and bitwise-XOR, computational overhead ran be reduced. Hence it is suitably and efficiently adaptive to dynamic multicast environment that membership change event frequently occurs.