• Convergence Security Journal
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• v.5 no.1
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• pp.85-92
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• 2005

For an efficient role based access control in highly distributed computing environment to reduce management cost, we utilize attribute certificates. Especially highly distributed computing environments such as ubiquitous computing environments which cannot have global or broad control, need another attribute certificate management technique. The techniques for transmission of the attribute certificates and management of the group keys should be considered to reduce management cost. For better performance we structure attribute certificates. We group roles and make the role group relation tree. It results secure and efficient role renewing and distribution. For scalable attribute certificate distribution, multicasting packets are used. We take into account the packet loss and quantifying performance enhancements of structuring attribute certificates.

• Journal of Korea Multimedia Society
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• v.13 no.4
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• pp.575-581
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• 2010

With widespread use of the Internet and improvements in streaming media and compression technology, digital music, video, and image can be distributed instantaneously across the Internet to end-users. However, most conventional Digital Right Management are often not secure and not fast enough to process the vast amount of data generated by the multimedia applications to meet the real-time constraints. The SVC offers temporal, spatial, and SNR scalability to varying network bandwidth and different application needs. Meanwhile, for many multimedia services, security is an important component to restrict unauthorized content access and distribution. This suggests the need for new cryptography system implementations that can operate at SVC. In this paper, we propose a new scrambling encryption for reserving the characteristic of scalability in MPEG4-SVC. In the base layer, the proposed algorithm is applied and performed the selective scambling. And it encrypts various MVS and intra-mode scrambling in the enhancement layer. In the decryption, it decrypts each encrypted layers by using another encrypted keys. Throughout the experimental results, the proposed algorithms have low complexity in encryption and the robustness of communication errors.

• The Transactions of the Korea Information Processing Society
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• v.7 no.8
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• pp.2298-2309
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• 2000

This paper proposes the multidimensioa! nested attribute indexing techniques (MD- NAI) in object-oriented databases using a multidimensional index structure. Since most conventional indexing techniques for object oriented databases use a one-dimensional index stnlcture such as the B-tree, they do not often handle complex qUlTies involving both nested attributes and class hierarchies. We extend a tunable two dimensional class hierachy indexing technique(2D-CHI) for nested attributes. The 2D-CHI is an indexing scheme that deals with the problem of clustering ohjects in a two dimensional domain space that consists of a kev attribute dOI11'lin and a class idmtifier domain for a simple attribute in a class hierachy. In our extended scheme, we construct indexes using multidimensional file organizations that include one class identifier domain per class hierarchy on a path expression that defines the indexed nested attribute. This scheme efficiently suppoI1s queries that involve search conditions on the nested attribute represcnted by an extcnded path expression. An extended path expression is a one in which a class hierarchy can be substituted by an indivisual class or a subclass hierarchy in the class hierarchy.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.23 no.5
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• pp.885-896
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• 2013

MTC(Machine Type Communications), providing a variety of services anytime and anywhere by connecting the cellular network to the machine and things without human intervention, is being considered as a major challenge of the next-generation communications. Currently, When a massive MTC devices simultaneously connect to the network, each MTC device needs an independent access authentication process. Because of this process, authentication signaling congestion and overload problems will cause in LTE-Advanced. In this paper, we propose a group-based authentication protocol and a key management protocol. For managing the MTC devices as group units, the proposed protocol elects a group leader and authentications only once with the core network. After the authentication is completed, a group leader manages the rest members and MME(Mobility Management Entity) by constructing a binary tree. Finally, the propose protocol analysis show that the proposed protocol not only can reduces the authentication signaling which generated in between the MTC devices and the core network but also can manages the MTC devices, efficiently.

• Journal of KIISE:Databases
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• v.32 no.5
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• pp.498-508
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• 2005

A shape data is used one oi most important feature for image retrieval as data to reflect meaning of image. Especially, structural feature of shape is widely studied because it represents primitive properties of shape and relation information between basic units well. However, most structural features of shape have the problem that it is not able to guarantee an efficient search time because the features are expressed as graph or tree. In order to solve this problem, we generate curvature-based morphological graph, End design key to cluster shapes from this graph. Proposed this graph have contour features and morphological features of a shape. Shape retrieval is accomplished by stages. We reduce a search space through clustering, and determine total similarity value through pattern matching of external curvature. Various experiments show that our approach reduces computational complexity and retrieval cost.

• Journal of Convergence for Information Technology
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• v.10 no.11
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• pp.16-22
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• 2020

Since it is difficult for individual power producers and non-professionals who lack basic knowledge to control, manage, and operate facilities through EMS (Energy Management System), augmented reality and virtual reality monitoring systems are applied. However, in the existing systems, data access efficiency is inferior due to the process of analyzing column values for analog signal values collected from sensors and converting data after combining the columns. In addition, high-speed operation processing is difficult due to a large number of indexes for accommodating access patterns for various analog signal waveforms. Therefore, in this paper, a bitmap generator is inserted into a non-tree structure to convert the data collected from power facilities into physical property information, and the converted information is encrypted with a common key, so that the resources for the resources shared between each device are We propose a method of exchanging data for an augmented reality-based power system that is controlled by measurement.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.1080-1083
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• 2005

Can speak that DTD is meta data that define meaning of expressed data on XML document. Therefore, in case DTD information is damaged this information to base security of XML document dangerous. Not that attach digital signature on XML document at send-receive process of XML document in this research, proposed method to attach digital signature to DTD. As reading DTD file to end first, do parsing, and store abstracted element or attribute entitys in hash table. Read hash table and achieve message digest if parsing is ended. Compose and create digital signature with individual key after achievement. When sign digital, problem that create entirely other digest cost because do not examine about order that change at message digest process is happened. This solved by method to create DTD's digital signature using DOM that can embody tree structure for standard structure and document.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.1
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• pp.73-83
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• 2018

There has been increasing interest from NIST and other companies in studying post-quantum cryptography in order to resist against quantum computers. Multivariate polynomial based, code based, lattice based, hash based digital signature, and isogeny based cryptosystems are one of the main categories in post quantum cryptography. Among these categories, isogeny based cryptosystem is known to have shortest key length. In this paper, we implemented Supersingular Isogeny Diffie-Hellman (SIDH) protocol efficiently on low-end mobile device. Considering the device's specification, we select supersingular curve on 523 bit prime field, and generate efficient isogeny computation tree. Our implementation of SIDH module is targeted for 32bit environment.

• Journal of KIISE:Information Networking
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• v.28 no.2
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• pp.262-276
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• 2001

Recently much research for developing forwarding table that support fast router without employing both special hardware and new protocols. This article introduces a new forwarding data structure based on the software to enable forwarding lookup to be penormed at giga-bit speed. The forwarding table is known as a bottleneck of the routers penormance due to its high complexity proportional to the forwarding table size. The recent research that based on the software uses a Patricia trie and its variants. and also uses a hash function with prefix length key and others. The proposed forwarding table structure construct a forwarding table by the bit stream array in which it constructs trie from routing table prefix entries and it represents each pointer pointing the child node and the associated forwarding table entry with one bit The trie structure and routing prefix pointer need a large memory when representing those by linked-list or array. but in the proposed data structure, the needed memory size is small enough since it represents information with one bit. Additionally, by use a lookup method that start searching at desired middle level we can shorten the search path. The introduced data structure. called bit-map trie shows that we can implement a fast forwarding engine on the conventional Pentium processor by reducing the backbone routing table fits into Level 2 cache of Pentium II processor and shortens the searching path. Our experiments to evaluate the performance of proposed method show that this bit-map trie accomplishes 5.7 million lookups per second.

• The Journal of Society for e-Business Studies
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• v.18 no.4
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• pp.45-65
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• 2013

A design file can get larger in size as the complexity of the target object increases. A large design file may reside in a large parallel computing system, such as cloud computing systems, and many designers may work concurrently on the same design file. In such a case, it is obvious that we need some kind of protection mechanism so that each user can access only the area of the file he or she is entitled to. Two approaches can be taken for this problem: one is the traditional access control mechanisms and the other encryption techniques. We take the latter approach to ensure the safety of the file even in public domain such as clouding systems, and in this paper, we suggest an encryption scheme for a file where the file is encrypted in multi-layer so that each user is allowed to access the file only at the layer for which the user has the proper access right. Each layer of the file is encrypted with different keys and these keys are exposed only to those who have the right access permit. The paper explains the necessary file format to achieve this goal and discusses the file manipulation functions to handle this new file format.