• 정보보호학회논문지
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• 제26권6호
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• pp.1421-1430
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• 2016

본 논문에서 우리는 ARX 구조를 가지는 블록 암호에 대한 차분 경로 탐색을 효율적으로 수행하는 방법에 대해 제안한다. 우리는 두 가지 기법을 이용하여 A. Biryukov 등이 제안한 차분 경로 자동 탐색하는 알고리즘을 최적화하였고, 이를 블록 암호 SPECK에 적용하여 Birykov의 결과보다 2~3배 향상된 결과를 얻었다. 이는 ARX 구조를 가지는 블록 암호에 대한 기제안된 결과보다 더 좋은 차분 경로를 찾는데 도움을 줄 수 있다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권1호
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• pp.435-451
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• 2019

Impossible differential cryptanalysis is an essential cryptanalytic technique and its key point is whether there is an impossible differential path. The main factor of influencing impossible differential cryptanalysis is the length of the rounds of the impossible differential trail because the attack will be more close to the real encryption algorithm with the number becoming longer. We provide the upper bound of the longest impossible differential trails of several important block ciphers. We first analyse the national standard of the Russian Federation in 2015, Kuznyechik, which utilizes the 16-byte LFSR to achieve the linear transformation. We conclude that there is no any 3-round impossible differential trail of the Kuznyechik without the consideration of the specific S-boxes. Then we ascertain the longest impossible differential paths of several other important block ciphers by using the matrix method which can be extended to many other block ciphers. As a result, we show that, unless considering the details of the S-boxes, there is no any more than or equal to 5-round, 7-round and 9-round impossible differential paths for KLEIN, Midori64 and MIBS respectively.

• 한국의류학회지
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• 제28권5호
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• pp.570-581
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• 2004

The purpose of this study is to analyze the acceptance and interpretation of pop musician's image in the Korean youth subculture, Fan Costume play(Fancos). Fancos subculture took the most active attitude to accepts of the pop musician's image and therefore was assumed to have various and differential acceptance aspects. The ethnographic method was used in order to approach more closely from their point of view. The cultural activity of Fancos subculture was imitation and reappearance of pop musician's appearance. Actually Fancos is a kind of fan-culture which idolized Korean pop music star. The acceptance of musician's appearance in Fancos is found out in two aspects. One is passive acceptance aspects that inforces conformity of star fashion and follows servilely ideal body image which promoted by cultural industry. The other is unique acceptance aspects that Fancos members interpret the musician's image in their own way. Those members experience pleasure through their own meaning. And homology of their appearance makes a distinction between of themselves from other youth and intensifies their group identity. As above analyzed, Fancos subculture has differential acceptance of pop music star's image comparing to other youth and even their stylistic appearance reflects not only their fandom but also their own meaning. Consequently, pop musician's image as a popular cultural text is accepted not equal to all populace but dissimilar along with contexts and trails of the acceptance group.

• 농업과학연구
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• 제38권1호
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• pp.109-113
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• 2011

The purpose of this study was to examine the potentiality of urban forest roads as an environment for enhancing physical fitness. Six male university students participated in the study as subjects. The subjects walked on an urban forest road for 30 minutes. As a control experiment, they also walked on a national park trail for 30 minutes. Subjects' heart rates were monitored during the walks to calculate the ratio of the average time their heart rates were within the target range (from 60% to 80% of the maximal heart rate) for Enhancing Physical Fitness. After the walks, images of the spaces were analyzed using the semantic differential (SD) method. During the walk on the urban forest road, subjects' heart rates were within the target range 63.3% of the time, and lower than the target range 36.7% of the time. During the control experiment on the national park trail, subjects' heart rates were within the target range only 23.3% of the time, and higher than the target range 76.7% of the time. From the spatial perception evaluation using the SD method, subjects' comfortable and natural feelings when they were on the national park trail were significantly greater than when they were on the urban forest trail, but there were no differences in terms of other SD descriptors, such as friendliness and likeability. The results of our study indicate that the urban forest road provides a good environment for walking to enhance physical fitness. Although not as close to nature as national park trails, urban forest roads offer similar natural environments and have a high potentiality for serving as leisure spaces for urban residents who seek physical activities.

• 정보보호학회논문지
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• 제30권3호
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• pp.325-336
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• 2020

비선형 불변 공격은 비교적 간단한 구조의 키 스케줄을 갖는 경량 블록암호에서 필수적으로 고려되어야 할 공격이다. 간단한 구조의 키 스케줄을 갖는 경량 블록암호가 비선형 불변 공격에 저항성을 보이는 방법으로 가장 잘 알려진 것은 라운드 키 간의 차분 중 알려진 것들의 집합에서 선형계층에 대해 불변인 최소의 선형공간의 크기가 블록 크기와 같은지를 확인하는 것이다. 본 논문에서는 다음과 같은 연구 결과를 제시한다. 설계자 관점에서 비트 순열을 선형계층으로 사용하는 SPN 구조 경량 블록암호는 라운드 키 간의 차분의 종류가 한가지여도 비선형 불변 공격에 안전할 수 있음을 증명하고, 그러한 비트 순열의 형태와 개수를 제안한다. 또한, PRESENT 구조 블록암호는 비선형 불변 공격에 저항성을 갖기 위해 적어도 두 종류의 라운드 키 간의 차분이 필요함을 전수조사를 통해 보이며, 두 종류의 라운드 키 간의 차분을 필요로 하는 비트 순열을 사용해도 차분 공격에 대한 저항성이 오히려 증가할 수 있음을 보인다. 마지막으로 GIFT의 S-box를 사용하면서 BOGI 설계 논리를 유지하는 모든 비트 순열의 불변 성분 분포를 통해, 변형된 GIFT 구조 블록암호는 비선형 불변 공격에 저항성을 갖기 위해 적어도 8종류의 라운드 키 간의 차분이 필요함을 보인다.