• Journal of KIISE:Databases
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• v.34 no.1
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• pp.1-17
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• 2007

As XML is becoming a de facto standard for distribution and sharing of information, the need for an efficient yet secure access of XML data has become very important. To enforce the fine-level granularity requirement, authorization models for regulating access to XML documents use XPath which is a standard for specifying parts of XML data and a suitable language for both query processing. An access control environment for XML documents and some techniques to deal with authorization priorities and conflict resolution issues are proposed. Despite this, relatively little work has been done to enforce access controls particularly for XML databases in the case of query access. Developing an efficient mechanism for XML databases to control query-based access is therefore the central theme of this paper. This work is a proposal for an efficient yet secure XML access control system. The basic idea utilized is that a user query interaction with only necessary access control rules is modified to an alternative form which is guaranteed to have no access violations using tree-aware metadata of XML schemes and set operators supported by XPath 2.0. The scheme can be applied to any XML database management system and has several advantages over other suggested schemes. These include implementation easiness, small execution time overhead, fine-grained controls, and safe and correct query modification. The experimental results clearly demonstrate the efficiency of the approach.

• Journal of Platform Technology
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• v.12 no.2
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• pp.45-57
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• 2024

Smart cities are the product of modern urban planning that seeks to innovate information and communication technology and improve the quality of urban life. For the efficient operation of smart cities, data collected, stored, and processed in real time is a key resource. Therefore, data from smart cities collected in various fields must be managed safely, and personal information protection is paramount. In this study, a smart city data security model using blockchain technology was proposed to safely manage smart city data. The proposed model integrates IPFS into the blockchain network to distribute and store data to ensure data confidentiality and integrity, and encrypts data using CP-ABE to efficiently control access to data from users. In addition, privacy was guaranteed while enhancing the usability of data by using Homomorphic Encryption with data access control policies.

• Journal of the Korea Society of Computer and Information
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• v.19 no.11
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• pp.97-103
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• 2014

The access control means the process to record and manage access restrictions and permits for protecting information in records. This paper emphasizes the control of access and authorization based on the roles and the data using activities of users as task performers. Also, it requires to gain the necessary approval in advance for important tasks such as mass inquiry and change on important information to influence the very existence of the whole organization. And then, it suggests that it is necessary to control some session of information with non-activity for certain time. Generally, this paper is to explain security elements of access control through various cases.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.639-641
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• 2002

In this paper, we proposed the multiple access control of RS232C Serial Communications protocol using collision sense method. The communications wires of data transmission and reception are tied together through the buffer each to connect to the multiple communication channels. The hardware interface and control program are designed to build the prototype system and the experimental multiple access communications network is built by multiple PC systems and the transfer completion rate results are shown.

• Journal of KIISE:Databases
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• v.32 no.2
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• pp.193-203
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• 2005

XML (extensible Markup Language) is recognized as a standard of data representation and transmission on Internet. XPath is a standard for specifying parts of XML documents anda suitable language for both query processing and access control of XML. In this paper, we use the XPath expression for representing user queries and access control for XML. And we propose an access control method for XML, where we control accesses to XML documents by filtering query XPath expressions through access control XPath expressions. In the proposed method, we directly search XACT (XML Access Control Tree) for a query XPath expression and extract the access-granted parts. The XACT is our proposedstructure, where the edges are structural summary of XML elements and the nodes contain access-control information. We show the query XPath expressions are successfully filtered through the XACT by our proposed method, and also show the performance improvement by comparing the proposed method with the previous work.

• Journal of KIISE
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• v.44 no.4
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• pp.352-362
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• 2017

This paper analyzes security threats in Security Enhanced (SE) Android and proposes a new technique to efficiently protect application data including private information on rooted Android phones. On an unrooted device, application data can be accessed by the application itself according to the access control models. However, on a rooted device, a root-privileged shell can disable part or all of the access control model enforcement procedures. Therefore, a root-privileged shell can directly access sensitive data of other applications, and a malicious application can leak the data of other applications outside the device. To address this problem, the proposed technique allows only some specific processes to access to the data of other applications including private information by modifying the existing SEAndroid Linux Security Module (LSM) Hook function. Also, a new domain type of process is added to the target system to enforce stronger security rules. In addition, the proposed technique separates the directory type of a newly installed application and the directory type of previously installed applications. Experimental results show that the proposed technique can effectively protect the data of each application and incur performance overhead up to or less than 2 seconds.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.95-98
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• 2006

Data collected by sensors in field are transmitted to the base station gathering all of data. Because sensors have to gather data in surroundings and periodically transmit data to the base station, it makes energy consumed much. In this paper, we propose the scheme that is to avoid traffic congestion with achievement of energy efficiency, so collected data is transmitted efficiently. This is to adjust transmission rate differently in case of increasing or decreasing traffic and minimize the energy consumption with setting ideal options up basic CSMA(Carrier Sense Multiple Access) protocol in each sensor. Through the simulation, we find the ideal CSMA options and apply the proposed scheme of traffic control mechanism to them, then show energy efficiency and effective traffic control mechanism.

• Smart Media Journal
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• v.10 no.1
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• pp.88-98
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• 2021

As blockchain technology has emerged as a security issue for IoT, technology which integrates block chain into IoT is being studied. In this paper is a research concerning token-based IoT service access control technology for data sharing, which propose a possessor focused data sharing technic by using the permissioned blockchain. To share IoT health data, a Hyperledger Fabric Network consisting of three organizations was designed to provide a way to share data by applying different access control policies centered on device owners for different services. In the proposed system, the device owner issues access control tokens with different security levels applied to the participants in the organization, and the token issue information is shared through the distributed ledger of the HFN. In IoT, it is possible to lightweight the access control processing of IoT devices by granting tokens to service requesters who request access to data. Furthmore, by sharing token issuance information among network participants using HFN, the integrity of the token is guaranteed and all network participants can trust the token. The device owners can trust that their data is being used within their authorized rights, and control the collection and use of data.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.9
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• pp.21-31
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• 2013

A ciphertext policy-attribute based encryption(CP-ABE) scheme can be used to realize access control mechanism without a trusted server. We propose an attribute-based access control mechanism by incorporating a CP-ABE scheme to ensure only authorized users can access the sensitive data. The idea of CP-ABE is to include access control policy in the ciphertexts, in which they can only be decrypted if a user possesses attributes that pass through the ciphertext's access structure. In this paper, we prove a secure CP-ABE scheme where the policy can be expressed in non-monotonic access structures. We further compare the performance of our scheme with the existing CP-ABE schemes.

• Proceedings of the KIEE Conference
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• 2007.04a
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• pp.409-412
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• 2007

Demand for the technology for access to device control network in industry and for access to building automation system via internet is on the increase. In such technology integration of a device control network with a data network such as internet and organizing wide-ranging DCS(distributed control system) is needed, and it can be realized in the framework of VDN(virtual device network). Specifications for device control network and data network are quite different because of the differences in application. So a router that translates the communication protocol between device control network and data network, and efficiently transmits information to destination is needed for implementation of the VDN(virtual device network). This paper proposes the concept of NCS(networked control system) based on VDN(virtual device network) and suggests the routing algorithm that uses embedded system.