• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.7
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• pp.325-330
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• 2017

Bluetooth 4.0 is a technology suitable for the Internet of things that is used for communication between various devices. This technology is suitable for developing a service by combining with automobiles. In this study, a security authentication system was designed by linking Bluetooth 4.0 technology and a vehicle system as an implementation example of an object internet service. A procedure was designed for security authentication and an authentication method is proposed using a data server. When the security authentication function is provided, various additional services can be developed using the information collection function of the risk notification and user action history. In addition, BLE (Bluetooth Low Energy) technology, which is a wireless communication technology that enables low-power communication and low-power communication in the process of the standardization and development of Bluetooth technology and technology, improves the battery life through the use of RFID or NFC This study expanded the range possible. The security service can be extended by expanding the scope of authentication by the contactless type. Using the proposed system, a customized service can be provided while overcoming the problems of an existing radio frequency (RF)-based system, portability, and battery usage problem.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.2
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• pp.49-60
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• 2011

Instant Messenger is one of the most popular communication service when translating message or data each other through Internet. For digital crime investigation, therefore, it is obviously important to obtain communication trace and contents derived from Instant Messenger. This is because that gathering traditional communication histories also have been important until now. However, extracting communication trace and contents are not easy because they are generally encrypted or obfuscated in local system, futhermore, sometimes they are located at server computer for Instant Messenger. This paper researches on extracting communication histories against NateOn, BuddyBuddy, Yahoo! messenger and Mi3 messenger, and obtaining user password or bypassing authentication system to Instant Messenger Service when a user use auto-login option.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.6
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• pp.1509-1522
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• 2018

The purpose of this study is to support flexible authentication functions in various services using various types of user information. Rather than requiring the same level of authentication for all services, the goal is to identify the level of authentication at the time of user authentication and to increase convenience and efficiency by dynamically granting authority. In this paper, we propose POSCAL (Protocol of Service Control by Authentication Level) protocol which can control service access based on various local authentication information. To verify the function of the authentication framework, we developed the electronic wallet service based on the POSCAL authentication framework and evaluated the implementation function based on the use case scenario. The proposed protocol satisfies user and message authentication, confidentiality of authentication information, integrity of authentication history, non - repudiation of authorization, and access control by service according to security level.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.6
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• pp.1113-1120
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• 2022

Recently, the investigation has been difficult due to the emergence of messengers that encrypt and store data for the purpose of protecting personal information and provide services such as end-to-end encryption with a focus on security. Accordingly, the number of crime cases using security messengers is increasing, but research on data decoding for security messengers is needed. Element security messengers provide end-to-end encryption functions so that only conversation participants can check conversation history, but research on decoding them is insufficient. Therefore, in this paper, we analyze the instant messenger Element, which provides end-to-end encryption, and propose a plaintext verification of the history of encrypted secure chat rooms using decryption keys stored in the Windows Credential Manager service without user passwords. In addition, we summarize the results of analyzing significant general and secure chat-related artifacts from a digital forensics investigation perspective.

• Korean Security Journal
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• no.29
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• pp.87-113
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• 2011

Korean security industry has history of more than half a century, and it is growing fast. Private security industry contributes not only to livelihood safety, but also to national security. The area of the industry is being expanded. Security Act is closely related to the security industry, and has contributed to the growth of private security industry sector. Security Act of Korea, which was established in 1976, was originally made after Japanese Security Act. But nowadays, Korean Security Act is as systematic as the Japanese act. However, for 10 years, Security Act of Korea has been stagnant, not able to reflect security industries' demand. The writer has contributed to the development of Security Act. In 1995, the writer wrote the basic framework of Security Instructor Qualifications System and drafted Security Act in 2002. There are currently many problems in existing Security Act, but there are four representative problems. (1) No more establishment of new security sector, (2) excessively slack qualification criteria, (3) the education system for guards, (4) the security Instructor examination system. This paper derives problems of current Security Act, and suggests solutions for them. Not only the academic world, but all of us should pay attention to the revision of Security Act.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.1
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• pp.72-80
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• 2016

Recently, IM(Instant Messenger) of KakaoTalk is being used on smart devices such as smartphones. Because IM service can carry user and/or suspector's various information including life style, geographical position, psychology and crime history, forensic analysis on IM service is desirable. But, forensic analysis for KakaoTalk is not well studied yet. This paper studies a proper forensic method for KakaoTalks, finds artifacts location, reconstruct the list of contacts and the chronology of the messages that have been exchanged by users. Proposed methodology and analyzed information can provide a basic platform for forensic tool.

• Convergence Security Journal
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• v.21 no.2
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• pp.11-18
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• 2021

To protect tangible and intangible assets, most of the companies are conducting information protection monitoring by using various security equipment in the IT service network. As the security equipment that needs to be protected increases in the process of upgrading and expanding the service network, it is difficult to monitor the possible exposure to the attack for the entire service network. As a countermeasure to this, various studies have been conducted to detect external attacks and illegal communication of equipment, but studies on effective monitoring of the open service ports and construction of illegal communication monitoring system for large-scale service networks are insufficient. In this study, we propose a framework that can monitor information leakage and illegal communication attempts in a wide range of service networks without large-scale investment by analyzing 'Netflow statistical information' of backbone network equipment, which is the gateway to the entire data flow of the IT service network. By using machine learning algorithms to the Netfllow data, we could obtain the high classification accuracy of 94% in identifying whether the Telnet service port of operating equipment is open or not, and we could track the illegal communication of the damaged equipment by using the illegal communication history of the damaged equipment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.4
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• pp.777-785
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• 2016

IM(Instant Messenger) chatting service can carry user's various information including life style, geographical position, and psychology & crime history and thus forensic analysis on the IM service is desirable. But, forensic analysis for KakaoTalk's chatting service is not well studied yet. For this reason, we study KakaoTalk's forensic analysis focusing on chatting service. This paper first details a general method of IM forensics investigating the previous articles about IM forensics although there are not many articles. Second, we discuss methodologies for IM forensics wherein we present analysis of table structure and method for reconstruction of chatting message. These result in the basic element of forensic tools of KakaoTalk chatting message. Last, we compare artifacts of KakaoTalk with that of WhatsApp. We conclude that these applications are, at least, different in that table structures and the ways to reconstruct chatting messages are not same and therefore digital evidences or artifacts are not same and somewhat distinct.

• Journal of information and communication convergence engineering
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• v.8 no.2
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• pp.238-243
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• 2010

CSD is Active RFID based Container Security Device which is proposed by the U.S Department of Home Security. It is mounted inside the container to sense opening of the container door. ConTracer is the CSD which is developed in this research whose major features are sensing door opening status as well as history inquiring on internal environment and shock to the container by mounting the temperature/ humidity/ shock sensors. Moreover, its RFID frequency bandwidth uses 433MHz and 2.4GHz to correspond actively to the frequency used by different countries. This paper introduces the development trend of CSD, compares the ConTracer which is developed thru this research and other company's CSD, and introduces CSD System which is designed and established using ConTracer. Finally, the implemented CSD System is verified by applying the demonstration service to container distribution between Korea and China.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.1
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• pp.100-106
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• 2018

Since the concept of virtual currency called Bitcoin was announced in 2008, the blockchain technology, which is the basis of Bitcoin, is attracting attention as an important platform technology in the era of the 4th industrial revolution that can change our society in the future. Although Existing electronic financial transactions store and manage all transaction history at a reliable central organization such as government and bank, blockchain-based electronic financial transactions are composed of a distributed structure in which all participants participating in the transaction store and manage the transaction history, it is possible to secure transaction transparency while reducing system construction and operation costs. Besides the virtual currency that started with bit coins, the technology of these blockchains has been extended in various fields such as smart contracts and document management. The key technology area of this blockchain is security based on proven cryptographic technology to make it difficult to forge and hack, but there are security risks such as security vulnerabilities in the virtual currency trading service, We will discuss security risks in using virtual currency and discuss countermeasures. Especially security accidents of virtual currency exchanges are occurring frequently recently, the damage of users who trade the virtual currency is also increasing, we propose security threats and security countermeasures against virtual currency exchanges.