• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.4
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• pp.761-770
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• 2012

CAPTCHAs(Completely Automated Public Turing tests to tell Computer and Human Apart) have been widely used for preventing the automated attacks such as spam mails, DDoS attacks, etc.. In the early stages, the text-based CAPTCHAs that were made by distorting random characters were mainly used for frustrating automated-bots. Many researches, however, showed that the text-based CAPTCHAs were breakable via AI or image processing techniques. Due to the reason, the image-based CAPTCHAs, which employ images instead of texts, have been considered and suggested. In many image-based CAPTCHAs, however, the huge number of source images are required to guarantee a fair level of security. In 2008, Kang et al. suggested a new image-based CAPTCHA that uses test images made by composing multiple source images, to reduce the number of source images while it guarantees the security level. In their paper, the authors showed the convenience of their CAPTCHA in use through the use study, but they did not verify its security level. In this paper, we verify the security of the image-based CAPTCHA suggested by Kang et al. by performing several attacks in various scenarios and consider other possible attacks that can happen in the real world.

• Journal of Industrial Convergence
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• v.19 no.6
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• pp.37-47
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• 2021

Today, people share information and communicate with others using various information and communication media such as e-mail, smartphones, SNS, etc. However, it is being used in malicious attacks to send a large amount of illegal spam or to use it for fraud by using illegally collected personal information and devices that are vulnerable to security. Illegal spam, smishing, and fraudulent mail(SCAM) cause a lot of direct and indirect damage to companies and users, including not only social costs such as mental fatigue, but also unnecessary consumption of IT infrastructure resources and economic losses. Although there are regulations related to spam, violators of the law are still on the rise by circumventing the law, and victims are constantly occurring, so it is necessary to review what the problem is. This study examined domestic and foreign spam-related regulations and spam-related response activities, identified problems, and suggested improvement countermeasures. Through this study, it was intended to suggest directions for improving spam-related systems in order to block illegal spam and prevent fraudulent damage.

• Journal of Convergence for Information Technology
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• v.10 no.7
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• pp.20-32
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• 2020

This study is to develop and provide a personal information protection framework that enables IoT service providers to safely and systematically operate personal information of IoT service subjects in the overall process of providing IoT devices and services. To this end, a framework for personal information framework was derived through literature survey, and FGI with experts, it was divided into three stages, each of three stages: IoT service provision process and IoT personal information processing process. The study conducted an e-mail survey of related experts using AHP techniques to determine the importance of the components of the selected personal information protection framework. As a result, in the IoT service provision process, the IoT product and service design and development stage (0.5413) is the most important, and in the IoT personal information processing process, personal information protection in the collection and retention of personal information (0.5098) is the most important. Therefore, based on this research, as the IoT service is spreading, it is expected that a safe personal information protection framework will be realized by preventing security threats and personal information infringement accidents.