• Journal of the Korea Institute of Information Security & Cryptology
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• v.12 no.6
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• pp.59-69
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• 2002

Many Linear attacks have introduced after M. Matsui suggested Linear Cryptanalysis in 1993. The one of them is the method suggested by B. Kaliski and M. Robshaw. It was a new method using multiple linear approximations to attack for block ciphers. It requires less known plaintexts than that of Linear Cryptanalysis(LC) by Matsui, but it has a problem. In this paper, we will introduce the new method using multiple linear approximation that can solve the problem. Using the new method, the requirements of the known plaintexts is 5(1.25) times as small as the requirements in LC on 8(16) round DES with a success rate of 95%(86%) respectively. We can also adopt A Chosen Plaintext Linear Attack suggested by L. R. Knudsen and J. E. Mathiassen and then our attack requires about $2^{40.6}$ chosen plaintexts to recover 15 key bits with 86% success rate. We believe that the results in this paper contain the fastest attack on the DES full round reported so far in the open literature.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.44 no.1
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• pp.113-121
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• 2007

Commonly, in the Sensor Network that composed with multiple nodes uses Ad-hoc protocol to communicate each other. Each sensed data packets are collected by base node and processed by Host PC. But the Ad-hoc protocol is too vulnerable to Sinkhole attack, where the intruder attracts surrounding nodes with unfaithful routing information, and then performs selective forwarding or changes the data passing through it. The Sinkhole attack increases overhead over the network and boosts energy consumption speed to decrease network's life time. Since the other attacks can be easily adopted through sinkhole attack, the countermeasure must be considered carefully. In this paper, we proposed the Hop-depth algorithm that detects intruder in Sinkhole attack and colluded nodes. First, the proposed algorithm makes list of suspected nodes and identifies the real intruder in the suspected node list through the Hop-depth count value. And recalculates colluder's path information to find the real intruder. We evaluated the performance of the proposed algorithm using NS2. We compared and analyzed the success ratio of finding real intruder, false positive ratio, false negative ratio, and energy consumption.

• Journal of the Society of Disaster Information
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• v.2 no.1
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• pp.139-155
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• 2006

Over the past two decades suicide terrorism has become an ever-widening phenomenon. When suicide terrorism was first introduced in the Middle East it seemed that this new phenomenon was invincible and that it might change the innate imbalance between terror groups and their rivalry governments. This did not in fact occur. Looking at history of terrorism, it can be seen that suicide attacks are in actuality a very old modus operandi. However, contemporary suicide terrorism differs from such historical tactics, just as the whole phenomenon of terrorism differs from ancient modes of warfare. Modern suicide terrorism is aimed at causing devastating physical damage. through which it inflicts profound fear and anxiety. Its goal is to produce a negative psychological effect on an entire population rather than just the victims of the actual attack. The relatively high number of casualties guaranteed in such attacks, which are usually carried out in crowded areas, ensures full media coverage. Thus, suicide terrorism, ranks with other spectacular modus operandi such as blowing up airplanes in mid air or the use of Weapons of Mass Destruction as a sure means to win maximum effect. For the purposes of this paper a suicide terror attack is defined as a politically motivated violent attack perpetrated by a self-aware individual (or individuals) who actively and purposely causes his own death through blowing himself up along with his chosen target. The perpetrator's ensured death is a precondition for the success of his mission. The greatest potential risk suicide terrorism may pose in future is if terrorists carry out operations combined with other spectacular tactics such as blowing up airplanes or the use of Weapons of Mass Destruction. Such a combination will increase immensely the death toll of a single terror attack and will have a shocking psychological effect on public moral. At this level suicide terrorism would constitute a genuine strategic threat and would probably be confronted as such. This study portrays a general overview of the modern history of suicide terror activity worldwide, focusing on its main characteristics and the various aims and motivations of the terror groups involved. In addition, This study provides an overview what is to be done to prevent such terrorist attacks.

• The Korean Journal of Pain
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• v.36 no.1
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• pp.137-246
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• 2023

Background: To investigate the relationship between cutaneous allodynia (CA) and kinesiophobia, gastrointestinal system (GIS) symptom severity, physical activity, and disability, and to determine whether CA, pain, and disability were influencing factors for kinesiophobia, GIS symptoms, and physical activity in individuals with migraine. Methods: The study included 144 individuals with migraine. CA, kinesiophobia, GIS symptoms, physical activity level, and migraine-related disability were evaluated with the Allodynia Symptom Checklist, the Tampa Kinesiophobia Scale (TKS), the Gastrointestinal Symptom Rating Scale (GSRS), the International Physical Activity Questionnaire-7, and the Migraine Disability Assessment Scale (MIDAS), respectively. Results: The CA severity was only associated with TKS (r = 0.515; P < 0.001), GSRS-total (r = 0.336; P < 0.001), GSRS-abdominal pain (r = 0.323; P < 0.001), GSRS-indigestion (r = 0.257; P = 0.002), GSRS-constipation (r = 0.371; P < 0.001), and MIDAS scores (r = 0.178; P = 0.033). Attack frequency (P = 0.015), attack duration (P = 0.035) and presence of CA (P < 0.001) were risk factors for kinesiophobia. Attack frequency (P = 0.027) and presence of CA (P = 0.004) were risk factors for GIS symptoms. Conclusions: There was a relationship between the CA and kinesiophobia, GIS symptoms, and disability. CA and attack frequency were found to be risk factors for kinesiophobia and GIS symptoms. Migraine patients with CA should be assessed in terms of kinesiophobia, GIS, and disability. Lifestyle changes such as exercise and dietary changes and/or pharmacological treatment options for CA may increase success in migraine management.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.6
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• pp.1405-1417
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• 2017

Researches that apply the acceleration signal due to user's gait measured at the wearable device to the authentication technology are being introduced recently. The gait acceleration signal based authentication technologies introduced so far have assumed that an attacker can obtain a user's gait acceleration signal only by attaching accelerometer directly to user's body. And the practical attack method for gait acceleration signal based authentication technology is mimic attack and it uses a person whose physical condition is similar to the victim or identifies the gait characteristics through the video of the gait of the victim. However, mimic attack is not effective and attack success rate is also very low, so it is not considered a serious threat. In this paper, we propose Video Gait attack as a new attack method for gait acceleration signal based authentication technology. It is possible to know the position of the wearable device from the user's gait video signal and generate a signal that is very similar to the accelerometer's signal using dynamic equation. We compare the user's gait acceleration signal and the signal that is calculated from video of user's gait and dynamic equation with experiment data collected from eight subjects.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.1
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• pp.47-57
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• 2003

In this paper, we firstly evaluate the resistance of the reduced 5-round version of the block cipher CIKS-1 against linear cryptanalysis(LC) and show that we can attack full-round CIKS-1 with \ulcorner56-bit key through the canonical extension of our attack. A feature of the CIKS-1 is the use of both Data-Dependent permutations(DDP) and internal key scheduling which consist in data dependent transformation of the round subkeys. Taking into accout the structure of CIKS-1 we investigate linear approximation. That is, we consider 16 linear approximations with p=3/4 for 16 parallel modulo $2^2$ additions to construct one-round linear approximation and derive one-round linear approximation with the probability P=1/2+$2^{-17}$ by Piling-up lemma. Then we present 3-round linear approximation with 1/2+$2^{-17}$ using this one-round approximation and attack the reduced 5-round CIKS-1 with 64-bit block by LC. In conclusion we present that our attack requires $2^{38}$chosen plaintexts with a probability of success of 99.9% and about $2^{67-7}$encryption times to recover the last round key.(But, for the full-round CIKS-1, our attack requires about $2^{166}$encryption times)

• Proceedings of the Korean Nuclear Society Conference
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• 1997.10a
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• pp.713-718
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• 1997

In the TMI-2 accident, approximately twenty(20) tons of molten core material drained into the lower plenum. Early advanced light water reactor (LWR) designs assumed a lower head failure and incorporated various measures for ex-vessel accident mitigation. However, one of the major findings from the TMI-2 Vessel Investigation Project was that one part of the reactor lower head wall estimated to have attained a temperature of 1100$^{\circ}C$ for about 30 minutes has seemingly experienced a comparatively rapid cooldown with no major threat to the vessel integrity. In this regard, recent empirical and analytical studies have shifted interests to such in-vessel retention designs or strategies as reactor cavity flooding, in-vessel flooding and engineered gap cooling of the vessel Accurate thermohydrodynamic and creep deformation modeling and rupture prediction are the key to the success in developing practically useful in-vessel accident/risk management strategies. As an advanced in-vessel design concept, this work presents the COrium Attack Syndrome Immunization Structures (COASIS) that are being developed as prospective in-vessel retention devices for a next-generation LWR in concert with existing ex-vessel management measures. Both the engineered gap structures in-vessel (COASISI) and ex-vessel (COASISO) are demonstrated to maintain effective heat transfer geometry during molten core debris attack when applied to the Korean Standard Nuclear Power Plant(KSNPP) reactor. The likelihood of lower head creep rupture during a severe accident is found to be significantly suppressed by the COASIS options.

• Journal of Korean Neurosurgical Society
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• v.50 no.4
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• pp.322-326
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• 2011

Objective : Stenting of symptomatic intracranial stenosis has recently become an alternative treatment modality. However, urgent intracranial stenting in patients with intracranial stenosis following a transient ischemic attack (TIA) or minor stroke is open to dispute. We sought to assess the feasibility, safety, and effectiveness of urgent intracranial stenting for severe stenosis (>70%) in TIA or minor stroke patients. Methods : Between June 2009 and October 2010, stent-assisted angioplasty by using a balloon-expandable coronary stent for intracranial severe stenosis (>70%) was performed in 7 patients after TIA and 5 patients after minor stroke (14 stenotic lesions). Technical success rates, complications, angiographic findings, and clinical outcomes were retrospectively analyzed. Results : Stenting was successful in all 12 patients. The mean time from symptom onset to stenting was 2.1 days (1-8 days). Post-procedural angiography showed restoration to a normal luminal diameter in all patients. In-stent thrombosis occurred in one patient (n=1, 8.3%), and was lysed with abciximab. No device-related complications, such as perforations or dissections at the target arteries or intracranial hemorrhaging, occurred in any patient. The mortality rate was 0%. No patient had an ischemic event over the mean follow-up period of 12.5 months (range, 7-21 months), and follow-up angiography (n=7) revealed no significant in-stent restenosis (>50%). Conclusion : Urgent recanalization with stenting is feasible, safe, and effective in patients with TIA or acute minor stroke with intracranial stenosis of ${\geq}$ 70%.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.6
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• pp.1383-1392
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• 2019

Adversarial attack, which geneartes adversarial data to make target model misclassify the input data, is able to confuse real life applications of classification models and cause severe damage to the classification system. An Black-box adversarial attack learns a substitute model, which have similar decision boundary to the target model, and then generates adversarial data with the substitute model. Jacobian-based data augmentation is used to synthesize the training data to learn substitutes, but has a drawback that the data synthesized by the augmentation get distorted more and more as the training loop proceeds. We suggest data augmentation with 'decay factor' to alleviate this problem. The result shows that attack success rate of our method is higher(around 8.5%) than the existing method.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.5
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• pp.1079-1087
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• 2018

Binary scalar multiplication which is the main operation of elliptic curve cryptography is vulnerable to the side-channel analysis. Especially, it is vulnerable to the side-channel analysis which uses power consumption and electromagnetic emission patterns. Thus, various countermeasures have been studied. However, they have focused on eliminating patterns of data dependent branches, statistical characteristic according to intermediate values, or the interrelationships between data. No countermeasure have been taken into account for the secure design of the key bit check phase, although the secret scalar bits are directly loaded during that phase. Therefore, in this paper, we demonstrate that we can extract secret scalar bits with 100% success rate using a single power or a single electromagnetic trace by performing key bit-dependent attack on hardware implementation of binary scalar multiplication algorithm. Experiments are focused on the $Montgomery-L{\acute{o}}pez-Dahab$ ladder algorithm protected by scalar randomization. Our attack does not require sophisticated pre-processing and can defeat existing countermeasures using a single-trace. As a result, we propose a countermeasure and suggest that it should be applied.