• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.6B
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• pp.199-206
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• 2008

Broadcast encryption is a cryptographical primitive which is designed for a content provider to distribute contents to only privileged qualifying users through an insecure channel. Anyone who knows public keys can distribute contents by means of public key broadcast encryption whose technique can also be applicable to many other applications. In order to design public key broadcast encryption scheme, it should devise some methods that convert a broadcast encryption scheme based on symmetric key cryptosystem to a public key broadcast encryption. Up to this point, broadcast encryption scheme on trial for converting from symmetric key setting to asymmetric public key setting has been attempted by employing the Hierarchical Identity Based Encryption (HIBE) technique. However, this converting method is not optimal because some of the properties of HIBE are not quite fitting for public key broadcast schemes. In this paper, we proposed new converting method and an efficient public key broadcast encryption scheme Pub-PI which is obtained by adapting the new converting method to the PI scheme [10]. The transmission overhead of the Pub-PI is approximately 3r, where r is the number of revoked users. The storage size of Pub-PI is O($c^2$), where c is a system parameter of PI and the computation cost is 2 pairing computations.

• Journal of the Korea Society of Computer and Information
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• v.24 no.6
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• pp.29-35
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• 2019

In this paper, the effects of educational contents on job behavior, the effects of job behavior on job effectiveness and the effects of educational contents on job effectiveness were studied when working in the Software field. For this purpose, a questionnaire survey was conducted on the learning workers who conducted the training in the IT field, and 302 valid questionnaires were used for the analysis. The research model was set up to test exploratory factor and confirmatory factor analysis and hypothesis, and the research hypothesis was tested by applying structural equation. The effects of job behavior on job effectiveness were positively related to job satisfaction, customer orientation, and organizational commitment.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.1
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• pp.129-134
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• 2010

In this paper, we propose a redistribution mechanism of the content that is adapted to devices, which may have different display size and computing capabilities, in home network. The proposed system introduces a mechanism that the encrypted content compressed by H.264/SVC(Scalable Video Coding) scheme which has been standardized recently is provided to the device into a level of content suitable to each device capability. To efficiently superdistribute SVC content, this paper defines three requirements and proposes redistribution mechanism which satisfies these requirements using another licence that it is called 'Ticket'. Our system allows devices to redistribute the content freely in the domain using domain key.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.2
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• pp.139-149
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• 2023

CBDC has characteristics similar to e-payments in which all records are kept by logs, so it is difficult to satisfy the anonymity level of cash. Therefore, in this study, the CBDC model that encrypts all transaction contents using the Diffie-Hellman key sharing algorithm was presented to enhance anonymity. The proposed model provides unlinkability anduntraceability. In addition, a CBDC certificate that uses pseudonym is used. Through this certificate, illegal transactions that require tracking can be tracked later by authorized institutions.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.4
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• pp.234-241
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• 2014

xTo improve network inefficiency caused by network congestion around a content-source, content-centric networking (CCN) allows network nodes transmitting contents to temporarily cache received contents and then send back the cached contents if the nodes receive relevant request messages without forwarding the request messages to content-sources. However, because nodes receiving requested contents through CCN cannot recognize real senders of the received contents, the receivers need to verify each received contents before using them. But such a verification procedure can cause long service/operation delay. Hence, in this paper, we review the problem of contents verification, propose an improved verification procedure and evaluate its performance.

• The Journal of the Korea Contents Association
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• v.21 no.2
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• pp.499-506
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• 2021

Hackers' cyber attack techniques are becoming more sophisticated and diversified, with a form of attack that has never been seen before. In terms of information security vulnerability standard code (CVE), about 90,000 new codes were registered from 2015 to 2020. This indicates that security threats are increasing rapidly. When new security vulnerabilities occur, damage should be minimized by preparing countermeasures for them, but in many cases, companies are insufficient to cover the security management level and response system with a limited security IT budget. The reason is that it takes about a month for analysts to discover vulnerabilities through manual analysis, prepare countermeasures through security equipment, and patch security vulnerabilities. In the case of the public sector, the National Cyber Safety Center distributes and manages security operation policies in a batch. However, it is not easy to accept the security policy according to the characteristics of the manufacturer, and it takes about 3 weeks or more to verify the traffic for each section. In addition, when abnormal traffic inflow occurs, countermeasures such as detection and detection of infringement attacks through vulnerability analysis must be prepared, but there are limitations in response due to the absence of specialized security experts. In this paper, we proposed a method of using the security policy information sharing site "snort.org" to prepare effective countermeasures against new security vulnerability attacks.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06a
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• pp.173-174
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• 2010

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.11a
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• pp.38-38
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• 2004

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.5
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• pp.1077-1084
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• 2015

Security issues such as an illegal acquisition of personal information and identity theft happen due to using game bots in online games. Game bots collect items and money unfairly, so in-game contents are rapidly depleted, and honest users feel deprived. It causes a downturn in the game market. In this paper, we defined the growth types by analyzing the growth processes of users with actual game data. We proposed the framework that classify hard-core users and game bots in the growth patterns. We applied the framework in the actual data. As a result, we classified five growth types and detected game bots from hard-core users with 93% precision. Earlier studies show that hard-core users are also detected as a bot. We clearly separated game bots and hard-core users before full growth.

• The Journal of Korean Association of Computer Education
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• v.14 no.1
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• pp.55-67
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• 2011

Due to recent various online problems, the necessity of information security education has increased. The information security education was strengthened thanks to the informatics curriculum of middle school in 2007, but the educational fields lacked detailed educational materials that could be utilized. Thus to give appropriate information security education for elementary and middle school students, this research developed an unplugged activity for them. The activity was designed by applying Lickona's integrated ethical model and design patterns of unplugged activities, and developed through expert's review and pilot tests targeted to elementary school students. Developed activity was applied to 21 middle school students and the usability was evaluated. As results, first, the activity showed similar expectations from the previous activities. Second, persistence was also similar or higher compared to the previous activities, so the activity developed from this research secured the minimum usability. The unplugged activity developed from this research would give implications in producing various educational contents for information security education.