• Korean Security Journal
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• no.53
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• pp.109-133
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• 2017

The purpose of this study is to provide a general trends in recent terrorism in North America and Europe over the last five years. In particular the terrorism which occurred after 2012 shows the transition in trends as terrorists attacks civilians and public places(soft target) rather than targeting national facilities or specific people. For instance, the Parris terror attack and Barcelona vehicle attack shows this changes clearly. The terrorists appeared to attack ordinary people in urban places with high population density. Although the trends are changing, there are still few studies focusing on the current situation, and most of the previous studies have focused on changing in strategies and counter-terrorism in each country after the 9.11 terror. Meanwhile, studies examining the trends of terrorism have been limited to analyzing few cases or using relatively monolithic data of Global Terrorism Data(GTD). While the types of terrorism that occur recent years including 'new terrorism' in many respects, it seems to be difficult to classify with GTD data and/or case studies. Therefore, it is necessary to construct new data that perhaps grasp the recent trend of terrorism from different perspectives. In this point of view, this Based on this, this study collects terrorism data from North America and Europe for the past five years, by using the National Intelligence Service's annual report on terrorism as a sampling framework and analyse the trends and changes. The result shows similarities in the methods of attack, and the type of weapon they used. As vehicle attacks has been raised in few years, damage area has been widen and casualties also have been increased.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.2 s.302
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• pp.49-58
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• 2005

In this paper, we proposed a blind watermarking algerian to use characteristics of a scalar quantizer which is the recommended in the JPEG2000 and JPEG. The proposed algorithm shifts a quantization index according to the value of each watermark bit to prevent losing the watermark information during the compression by quantization. Therefore, the watermark is embedded during the process of quantization, not an additional process for watermarking, and is adaptively applied as a assigned quantizer according application areas. Before embedding process, a LFSR(Linear feedback shift register) rearranged the watermark for the security of the watermark itself and in the embedding process, a LFSR is used to hide the watermarking positions. Therefore the embedded watermark can he extracted by only the owner who knows the initial value of LFSR without the original image. The visual recognizable pattern such as a binary image was used as the watermark. The experimental results showed that the proposed algerian satisfies the robustness and imperceptibility corresponding to the major requirement of watermarking. The results showed the largest error rate to be $5.7\%$ for attack. The experimental result which compares the proposed algorithm with the Mohamed algorithm showed that the proposed algorithm was better than it, exactly $4\~5$ times for the attacks of JPEG and JPEG2000.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.2
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• pp.60-69
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• 2013

Highlighted by recent security breaches including Google, Western Energy Company, and the Stuxnet infiltration of Iranian nuclear sites, Cyber warfare attacks pose a threat to national and global security. In particular, targeted attacks such as APT exploiting a high degree of stealthiness over a long period, has extended their victims from PCs and enterprise servers to government organizations and critical national infrastructure whereas the existing security measures exhibited limited capabilities in detecting and countermeasuring them. As a solution to fight against such attacks, we designed and implemented a security monitoring system, which shares security information and helps cooperative countermeasure. The proposed security monitoring system collects security event logs from heterogeneous security devices, analyses them, and visualizes the security status using 3D technology. The capability of the proposed system was evaluated and demonstrated throughly by deploying it under real network in a ISP for a week.

• The KIPS Transactions:PartB
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• v.12B no.4 s.100
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• pp.421-428
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• 2005

A new method of Semi-fragile image watermarking which ensures the integrity of the contents of digital image is presented. Proposed watermarking scheme embeds watermark in the form of quantization noise on the wavelet transform coefficients in a specific mid frequency subbands selected from a wavelet packet decomposition based on energy distribution of wavelet transform coefficients. By controlling the strength of embedded watermark using HVS (Human Visual System) characteristic, it is imperceptible by a human viewer while robust against non-malicious attack such as compression for storage and/or transmission. When an attack is applied on the original image, it is highly probable that wavelet transform coefficients not only at the exact attack positions but also the neighboring ones are modified. Therefore, proposed authentication method utilizes whether both current coefficient and its neighbors are damaged. together. So it can efficiently detect and accurately localize attacks inflicted on the content of original image. Decision threshold for authentication can be user controlled for different application areas as needed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.10
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• pp.7211-7218
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• 2015

Tens of thousands of malicious codes are generated on average in a day. New types of malicious codes are surging each year. Diverse methods are used to detect such codes including those based on signature, API flow, strings, etc. But most of them are limited in detecting new malicious codes due to bypass techniques. Therefore, a lot of researches have been performed for more efficient detection of malicious codes. Of them, visualization technique is one of the most actively researched areas these days. Since the method enables more intuitive recognition of malicious codes, it is useful in detecting and examining a large number of malicious codes efficiently. In this paper, we analyze the relationships between malicious codes and Native API functions. Also, by applying the word cloud with text mining technique, major Native APIs of malicious codes are visualized to assess their maliciousness. The proposed malicious code analysis method would be helpful in intuitively probing behaviors of malware.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.3 no.1
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• pp.14-25
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• 1992

The present study was purposed to find out variables of childhood antisocial behavior. The variables consisted of social cognition competence(Peer perception. acquaintance perception, frustration situation perception). academic competence(Visual integration function. written expression function, grammar closure function). The subject in this study were 32 nine year old-fourteen year old antisocial behavior boys and 32 third grade in elementary school-second grade in middle school normal boys and girls. The results of this study were obtained as follows. 1) In peer perception antisocial behavior children perceived peer as more supportive than normals. In acquaintance perception. there was no difference between groups. 2) In frustration situation perception, normal children used intropunitive attack still more than antisocial behavior children and antisocial behavior children perceived frustration situation more sensitive than normals and they were less active in problem solving aspects than normals. 3) In Academic competence, antisocial behavior children have deficits in visual motor integration function, written expression function. grammar closure function.

• Journal of Korea Multimedia Society
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• v.7 no.9
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• pp.1294-1303
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• 2004

This paper proposes new block fragile watermarking for image authentication and integrity by using the existing pixel-based scheme and block-based scheme. The proposed scheme is performed as fellows. First, we choose LUT(Look Up Table) from each pixel of original image and information of the corresponding block. Next, we insert a watermark, modifying original image with values to compare binary original image with the watermark to be embedded. As a result, we provide the means to overcome some weakness of the existing scheme. Binary logo as watermark can be detected from watermarked image and altered location can also be detected by the unit of pixel or that of block in our scheme.

• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.4
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• pp.47-60
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• 2015

In this paper, we propose a simple and useful method using a port role to visualize the network attacks. The port role defines the behavior of the port from the source and destination port number of network session. Based on the port role, the port provides the brief security features of each node as an attacker, a victim, a server, and a normal host. We have automatically classified and identified the type of node based on the port role and security features. We detected and visualized the network attacks using these features of the node by the port role. In addition, we are intended to solve the problems with existing visualization technologies which are the reflection problem caused an undirected network session and the problem caused decreasing of distinct appearance when occurs a large amount of the sessions. The proposed method monitors anomalies occurring in an entire network and displays detailed information of the attacker, victim, server, and hosts. In addition, by providing a categorized analysis of network attacks, this method can more precisely detect and distinguish them from normal sessions.

• The Journal of the Korea Contents Association
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• v.5 no.6
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• pp.331-342
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• 2005

In this paper, we propose an efficient watermarking algorithm using block indexing. The proposed algorithm is a novel blind watermarking scheme using the indexed watermark value based on the spread spectrum method. The watermark insertion is allocated into index value of each block after dividing original image into sub-blocks. The watermark embedded in mappinged with index values of blocks, And the mappinged blocks convert to DCT and then the PN sequence embedded to middle frequency band. Consequently the watermark is expressed by index value of sub-blocks. The watermark extracted from the correlation of between PN sequence and watermarked image. Experimental results demonstrate that the watermarked image has a good quality in terms of imperceptibility and is robust against various attacks.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.5
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• pp.871-883
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• 2014

New types of attacks that mainly compromise the public, portal and financial websites for the purpose of economic profit or national confusion are being emerged and evolved. In addition, in case of 'drive by download' attack, if a host just visits the compromised websites, then the host is infected by a malware. Website falsification detection system is one of the most powerful solutions to cope with such cyber threats that try to attack the websites. Many domestic CERTs including NCSC (National Cyber Security Center) that carry out security monitoring and response service deploy it into the target organizations. However, the existing techniques for the website falsification detection system have practical problems in that their time complexity is high and the detection accuracy is not high. In this paper, we propose website falsification detection system based on image and code analysis for improving the performance of the security monitoring and response service in CERTs. The proposed system focuses on improvement of the accuracy as well as the rapidity in detecting falsification of the target websites.