• Journal of the Korea Institute of Information Security & Cryptology
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• 제13권5호
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• pp.81-90
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• 2003

Existing web-based system management software solutions show some limitations in time and space. Moreover, they possess such as shortcomings unreliable error message announcements and difficulties with real-time assistance suppers and emergency measures. In order to solve these deficiencies, Wireless Remote Control System was designed and implemented. Wireless Remote Control System is able to manage and monitor remote systems by using mobile communication devices for instantaneous control. The implementation of Wireless Remote Control System leads to these security Problems as well as solutions to aforementioned issues with existing web-based system management software solutions. Therefore, this paper has focused on the security matters related to Wireless Remote Control System. The designed security functions include mobile device user authentication and target system access control. For security verification of these security functions introduced CPN(Coloured Petri Nets) which is capable of expressing every possible state for each stage. And then in this paper was verified its security through PI(Place Invariant) based on CPN(Coloured Petri Nets). The CPN expression and analysis method of the proposed security function can also be a useful method for analyzing other services in the future.

• Journal of the Korea Institute of Information Security & Cryptology
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• 제13권5호
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• pp.39-48
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• 2003

AAA(Authentication, Authorization, Accounting) protocol is a framework that propose functions of AAA on multiple networks and platforms. AAA protocol is extending from previous RADIUS protocol to Diameter protocol. There are some Diameter applications for variety purpose. Diameter CMS Application makes Diameter messages more secure by using PKI. Diameter CMS Application establish DSA(Diameter Security Association) for end to end security. However the Application has some problems to establish DSA(Diameter Security Association), which can make Diameter system unstable. If one system lose DSA information for some system error - for example, reboot -, the secure communication between two nodes may not be possible. At the application such as MIP, even user registration can't be done. In this paper, we propose a mechannism for DSA re-establishment, and also show the result of the implementation.

• Journal of the Korea Institute of Information Security & Cryptology
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• 제17권5호
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• pp.15-25
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• 2007

According to augmentation about interesting and demanding of privacy over the rest few years, researches that provide anonymity have been conducted in a number of applications. The ad hoc routing with providing anonymity protects privacy of nodes and also restricts collecting network information to malicious one. Until recently, quite a number of anonymous routing protocols have been proposed, many of them, however, do not make allowance for authentication. Thus, they should be able to have vulnerabilities which are not only modifying packet data illegally but also DoS(denial of service) attack. In this paper, we propose routing protocol with providing both anonymity and authentication in the mobile ad hoc network such as MANET, VANET, and more. This scheme supports all of the anonymity properties which should be provided in Ad Hoc network. In addition, based on the group signature, authentication is also provided for nodes and packets during route discovery phase. Finally, route discovery includes key-agreement between source and destination in order to transfer data securely.

• Journal of the Korea Institute of Information Security & Cryptology
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• 제19권5호
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• pp.81-91
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• 2009

Recently, Chein et al proposed the ultralightweight strong authentication and strong integrity (SASI)protocol, where the tag requrires only simple bitwise operations. Since the tag does not support random number generator to generate a challenge nonce, an attacker can replay old messages and impersonate reader. However, all of the previous ultralightweight authentication schemes are vlunerable to various attacks: de-synk, eavesdropping, impersonating, tracking, DoS, disclosure etc. we analyze the problems of previous proposed ultrlightweight protocols, to overcome these security problems by using PRNG on the tag. Therefore, in this paper we propose a new lightweight RFID mutual authentication protocol that provides random number generator and bitwise operations, a security and an efficiency of the proposed schme analyze.

• Journal of the Korea Institute of Information Security & Cryptology
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• 제13권3호
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• pp.71-79
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• 2003

Existing web-based system management software solutions show some limitations in time and space. Moreover, hey possess such as shortcomings unreliable error message announcements and difficulties with real-time assistance supports and emergency measures. In order to solve these deficiencies, Wireless Remote Control System(W-RCS) was designed and implemented. W-RCS is able to manage and monitor remote systems by using mobile communication devices for instantaneous control. The implementation of W-RCS leads to these security problems as well as solutions to aforementioned issues with existing web-based system management software solutions. Therefore, this paper has focused on the security matters related to W-RCS. The security functions based on public key infrastructure include mobile device user authentication and target system access control. The W-RCS allows real-time user authentication, increases the flexibility of resource administrators and mobile device non, and provides not only uninterrupted services, but also safe mobile office environments.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제25권2호
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• pp.308-313
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• 2021

In this study, tweets about the 2019 Koreas-US DMZ Summit were collected along with a time sequence and analyzed by a sequential topic modeling method, Dynamic Topic Modeling(DTM). In microblogging services such as Twitter, unstructured data that mixes news and an opinion about a single event occurs at the same time on a large scale, and information and reactions are produced in the same message format. Therefore, to grasp a topic trend, the contextual meaning can be found only by performing pattern analysis reflecting the characteristics of sequential data. As a result of calculating the DTM after obtaining the topic coherence score and evaluating the Latent Dirichlet Allocation(LDA), 30 topics related to news reports and opinions were derived, and the probability of occurrence of each topic and keywords were dynamically evolving. In conclusion, the study found that DTM is a suitable model for analyzing the trend of integrated topics in a specific event over time.

• Smart Media Journal
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• 제10권4호
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• pp.71-79
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• 2021

One of the social aspects that changes as the use of the Internet becomes widespread is communication in online space. In the past, only one-on-one conversations were possible remotely, except when they were physically in the same space, but nowadays, technology has been developed to enable communication with a large number of people remotely through bulletin boards, communities, and social network services. Due to the development of such information and communication networks, life becomes more convenient, and at the same time, the damage caused by rapid information exchange is also constantly increasing. Recently, cyber crimes such as sending sexual messages or personal attacks to certain people with recognition on the Internet, such as not only entertainers but also influencers, have occurred, and some of those exposed to these cybercrime have committed suicide. In this paper, in order to reduce the damage caused by malicious comments, research a method for improving the performance of discriminate malicious comments through feature extraction based on parts-of-speech.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제26권7호
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• pp.1091-1097
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• 2022

In this paper, we implement the eXclusive OR-based Cast (XC) system that is a video streaming system using exclusive OR operations, and measure various performance metrics in wireless local area network (WLAN) environments. In addition, we investigate the performance improvement of the XC system considering various practical video streaming environments, while conventional studies analyzed the performance of XC through computer simulations in limited environments. To this end, we propose new control messages such as STR_REQ_MSG (SRM) that clients transmit to a video streaming server and STR_CON_MSG (SCM) that is used for the video streaming server to control the clients, and develop a new protocol by using the new control messages. According to the various measurement results using the implemented XC system, XC video streaming system can reduce the consumption of network bandwidth by 8.6% on average and up to 25% compared to the conventional video streaming system. In addition, the outage probability can be also reduced up to 76%.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제26권2호
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• pp.271-277
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• 2022

PBFT (Practical Byzantine Fault Tolerant) is a consensus algorithm that can achieve consensus by resolving unintentional and intentional faults in a distributed network environment and can guarantee high performance and absolute finality. However, as the size of the network increases, the network load also increases due to message broadcasting that repeatedly occurs during the consensus process. Due to the characteristics of the PBFT algorithm, it is suitable for small/private blockchain, but there is a limit to its application to large/public blockchain. Because PBFT affects the performance of blockchain networks, the industry should test whether PBFT is suitable for products and services, and academia needs a unified evaluation metric and technology for PBFT performance improvement research. In this paper, quantitative evaluation metrics and evaluation frameworks that can evaluate PBFT family consensus algorithms are studied. In addition, the throughput, latency, and fault tolerance of PBFT are evaluated using the proposed PBFT evaluation framework.

• Journal of the Korea Society for Simulation
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• 제18권3호
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• pp.61-71
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• 2009

The server redirection system replicates contents on replica servers in the distributed network environment. When users make a request for contents, the system can provide the contents much faster than the client-server network system. In the server redirection system, it is the most important to select the optimal replica server with user's information because many replica servers are geographically distributed. And, the system can serve contents to users flexibly if a redirector is well constructed. In this paper, the redirector makes a list of candidates suitable for user conditions by the decision tree method and calculates the availability of each replica server. And, the redirector selects the replica server with the highest availability. This paper also proposes an availability-based server redirection system that predicts the availability of each replica server in order to reduce the workload of replica servers and the repetitive communication messages between a redirector and replica servers. If a user accesses the network path for the replica server selected and noticed by the proposed system, the user can get contents effectively and efficiently.