• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.6
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• pp.1421-1430
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• 2016

In this paper, we suggest an advanced method searching for differential trails of block cipher with ARX structure. we use two techniques to optimize the automatic search algorithm of differential trails suggested by A. Biryukov et al, and obtain 2~3 times faster results than Biryukov's when implemented in block cipher SPECK. This results contribute to find better differential trails than previous results.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.2
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• pp.600-616
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• 2021

SIMON and SPECK are two families of lightweight block ciphers that have excellent performance on hardware and software platforms. At CRYPTO 2019, Gohr first introduces the differential cryptanalysis based deep learning on round-reduced SPECK32/64, and finally reduces the remaining security of 11-round SPECK32/64 to roughly 38 bits. In this paper, we are committed to evaluating the safety of SIMON cipher under the neural differential cryptanalysis. We firstly prove theoretically that SIMON is a non-Markov cipher, which means that the results based on conventional differential cryptanalysis may be inaccurate. Then we train a residual neural network to get the 7-, 8-, 9-round neural distinguishers for SIMON32/64. To prove the effectiveness for our distinguishers, we perform the distinguishing attack and key-recovery attack against 15-round SIMON32/64. The results show that the real ciphertexts can be distinguished from random ciphertexts with a probability close to 1 only by 2^8.7 chosen-plaintext pairs. For the key-recovery attack, the correct key was recovered with a success rate of 23%, and the data complexity and computation complexity are as low as 2⁸ and 2^20.1 respectively. All the results are better than the existing literature. Furthermore, we briefly discussed the effect of different residual network structures on the training results of neural distinguishers. It is hoped that our findings will provide some reference for future research.

• Journal of Platform Technology
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• v.11 no.1
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• pp.72-84
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• 2023

With the rise of the Internet of Things, the security of such lightweight computing environments has become a hot topic. Lightweight block ciphers that can provide efficient performance and security by having a relatively simpler structure and smaller key and block sizes are drawing attention. Due to these characteristics, they can become a target for new attack techniques. One of the new cryptanalytic attacks that have been attracting interest is Neural cryptanalysis, which is a cryptanalytic technique based on neural networks. It showed interesting results with better results than the conventional cryptanalysis method without a great amount of time and cryptographic knowledge. The first work that showed good results was carried out by Aron Gohr in CRYPTO'19, the attack was conducted on the lightweight block cipher SPECK-/32/64 and showed better results than conventional differential cryptanalysis. In this paper, we first apply the Differential Neural Distinguisher proposed by Aron Gohr to the block ciphers HIGHT and GOST to test the applicability of the attack to ciphers with different structures. The performance of the Differential Neural Distinguisher is then analyzed by replacing the neural network attack model with five different models (Multi-Layer Perceptron, AlexNet, ResNext, SE-ResNet, SE-ResNext). We then propose a Related-key Neural Distinguisher and apply it to the SPECK-/32/64, HIGHT, and GOST block ciphers. The proposed Related-key Neural Distinguisher was constructed using the relationship between keys, and this made it possible to distinguish more rounds than the differential distinguisher.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2003.10a
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• pp.112-117
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• 2003

• Korean Journal of Agricultural Science
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• v.49 no.1
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• pp.11-18
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• 2022

A disrupted immune system during pregnancy is involved in pregnancy complications, such as spontaneous abortion, preeclampsia, and recurrent pregnancy loss. This study examined the role of toll-like receptor (TLR) 4 and ASC (apoptosis-associated speck-like protein containing a CARD [c-terminal caspase recruitment domain]) in pregnancy complications using a lipopolysaccharide (LPS)-induced miscarriage mice model. Incidences of miscarriage and embryonic resorption were examined at 9.5 days of pregnancy in wild-type (WT), ASC knockout (KO), and TLR4 KO mice after injecting them with LPS. The fetuses and placenta were obtained after sacrifice at 15.5 days of pregnancy. A significantly lower frequency of fetus absorption was found in TLR4 KO mice, whereas corresponding absorption outcomes were strongly induced in the WT and ASC KO mice upon an LPS injection. As expected, TLR4 KO mice were resistant to LPS-induced abortion. A histological analysis of the miscarried placenta showed increasing levels of the eosin staining of spongiotrophoblast cells without any obvious difference between WT and ASC KO mice. These results suggest that TLR4 KO mice are resistant to LPS, which affects pregnancy persistence, whereas WT and ASC KO mice show high miscarriage rates due to LPS. Moreover, the ASC adaptor is not directly involved in LPS-induced miscarriages, and the NLRP3 inflammasome can be activated by other proteins in the absence of ASC.

• Mycobiology
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• v.46 no.2
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• pp.147-153
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• 2018

Certain beneficial microorganisms isolated from rhizosphere soil promote plant growth and induce resistance to a wide variety of plant pathogens. We obtained 49 fungal isolates from the rhizosphere soil of paprika plants, and selected 18 of these isolates that did not inhibit tomato seed germination for further investigation. Based on a seed germination assay, we selected four isolates for further plant tests. Treatment of seeds with isolate JF27 promoted plant growth in pot tests, and suppressed bacterial speck disease caused by Pseudomonas syringae pathovar (pv.) tomato DC3000. Furthermore, expression of the pathogenesis-related 1 (PR1) gene was higher in the leaves of tomato plants grown from seeds treated with JF27; expression remained at a consistently higher level than in the control plants for 12 h after pathogen infection. The phylogenetic analysis of a partial internal transcribed spacer sequence and the b-tubulin gene identified isolate JF27 as Aspergillus terreus. Taken together, these results suggest that A. terreus JF27 has potential as a growth promoter and could be used to control bacterial speck disease by inducing resistance in tomato plants.

• The Plant Pathology Journal
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• v.19 no.4
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• pp.203-204
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• 2003

Decayed samples of marketed mungbean sprout were collected from Sacheon, Suncheon, and Dangjin cities in Korea. Initial symptom on hypocotyls was dark-brown diamond speck, which developed into enlarged sunken brownish-black spot with irregular margin, followed by softening yellowish decay. Brown speck on cotyledon further developed into irregular lesions. This study isolated the fungus Colletotrichum sp. The fungal colony was pale orange, which turned greenish gray after 1 week at $25^{\circ}C$. Colony of reverse side in a petri dish was pink. Neither conidiomata nor setae were present in the culture. Typical fusiform conidia sized 7.5-15.0$\times$2.5-2.9 $\mu\textrm$were hyaline, aseptate, smooth, and had salmon color in mass. Conidiogenous cells were phialidic, hyaline, smooth, and cylindrical with terminal distinct collarette. Basedon these mycological characteristics, the casual organism was identified as Colletotrichum acutatum. This is first report of Colletotrichum acutatum in Korea.

• Research in Plant Disease
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• v.17 no.3
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• pp.376-380
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• 2011

The bacterial speck of tomato caused by Pseudomonas syringae pv. tomato leads to serious economic losses especially on fruits of susceptible genotype. Thus, Pseudomonas syringae pv. tomato is a plant quarantine bacterium in many countries including Korea. In this study, we developed specific PCR assays for detection of the bacterium from tomato seeds. A specific primer set is designed from the hrpZ gene for specific detection of Pseudomonas syringae pv. tomato. A 501 bp PCR product corresponding to hrpZ gene was amplified only form Pseudomonas syringae pv. tomato strains, but no PCR product was amplified from other tomato bacterial pathogens, such as Pseudomonas syringae pv. glycinea, P. syringae pv. maculicola, P. syringae pv. atropurpurea, P. syringae pv. morsprunorum, and from other P. syringae pathovar strains. The nested-PCR primer set corresponding to an internal fragment of the 501 bp sequence (hrpZ) gine was used to specific detection of Pseudomonas syringae pv. tomato in tomato seed. A 119 bp PCR product using nested PCR primer was highly specific and sensitive to detect low level of Pseudomonas syrigae pv. tomato in tomato seeds. We believe that the PCR assays developed in this study is very useful to detect Pseudomonas syringae pv. tomato from the tomato seeds.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.415-417
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• 2002

Images of microcalcification specks showed large variation in conventional radiographs of phantoms which are approved for mammography image quality standard by the American College of Radiology (ACR). This kind of variation is not appropriate for image quality standards because the number of specks are visually counted in images and that number is important in image quality evaluation. Our study using synchrotron radiation (SR) imaging revealed the overlapping of micro-sized air bubble(s) to some specks, and also the structural deformation or crackings. Eight phantoms approved by ACR from two different makers and an air-bubble phantom were examined. SR imaging was performed at a synchrotron radiation facility, SPring-8, in Japan. The image-detector was a fluorescent-screen optical-lens coupling system using a CCD camera with a spatial resolution of 6 $\square$m. Objects when imaged with longer sample-to-detector distance show edge enhancement due to a difference in refraction indices, that is refraction enhancement. Refraction-enhanced SR images revealed that some of specks carried foreign objects, which were proven to be air. In phantoms provided by one maker, attaching/overlapping airs were observed for 62 out of 150 specks (41%) , with a higher incidence for the smallest specks. A speck becomes hardly visible in a conventional radiograph when air(s) overlaps the majority part of a speck, though depending on the size of the air-inclusion and on its configuration. Those airs might have been adsorbed on a speck surface before being embedded and then introduced into the matrix together with specks. Our study using SR imaging has clearly shown the nature of defects in some mammography phantoms which seriously degrade the quality as an image standard.

• Review of KIISC
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• v.29 no.5
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• pp.31-36
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• 2019

초고속, 초저지연, 초연결 특성으로 대표되는 5G 시대가 도래함에 따라 새로운 통신 환경과 서비스 환경에 적합한 암호기술이 요구되고 있다. IoT 환경 등 자원이 제약된 기기를 위한 저면적/저전력 암호기술, 자율 주행 등 실시간 처리를 위한 저지연 암호기술 등 경량암호에 대한 요구사항 또한 다변화되고 있다. 본 고에서는 SPECK/SIMON, LEA 등으로 대표되는 경량 블록암호와 초저지연 암호기술에 대해 살펴보고 NIST에서 진행 중인 경량암호 공모사업을 소개한다.