• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.1
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• pp.15-23
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• 2017

Template attack is a powerful side-channel analysis technique which can be performed by an attacker who has a test device that is identical to target device. Template attack is consisted of building template in profiling phase and matching the target device using template that were calculated in profiling phase. One methods to improve the success rate of template attack is to better estimate template which is consisted sample mean and sample covariance matrix of gaussian distribution in template profiling. However restriction of power trace in profiling phase led to poor template estimation. In this paper, we propose new method to select noisy power trace in profiling phase. By eliminating noisy power trace in profiling phase, we can construct more advanced mean and covariance matrix which relates to better performance in template attack. We proved that the proposed method is valid through experiments.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.9
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• pp.55-64
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• 2012

Until now, Side Channel Attack has been known to be effective to crack decrypt key such as smart cards, electronic passports and e-ID card based on Chip. Combination of Masking and shuffling methods have been proposed practical countermeasure. Newly, S.Tillich suggests biased-mask using template attack(TA) to attack AES with masking and shuffling. However, an additional assumption that is acquired template information previously for masking value is necessary in order to apply this method. Moreover, this method needs to know exact time position of the target masking value for higher probability of success. In this paper, we suggest new practical method called Biasing Power Analysis(BPA) to find a secret key of AES based on masking-shuffling method. In BPA, we don't use time position and template information from masking value. Actually, we do experimental works of BPA attack to 128bit secret key of AES based on masking-shuffling method performed MSP430 Chip and we succeed in finding whole secret key. The results of this study will be utilized for next-generation ID cards to verify physical safety.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.11
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• pp.2221-2234
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• 2011

The fuzzy vault scheme has emerged as a promising solution to user privacy and fingerprint template security problems. Recently, however, the fuzzy vault scheme has been shown to be susceptible to a correlation attack. This paper proposes a novel scheme for one-time templates for fingerprint authentication based on the fuzzy vault scheme. As in one-time passwords, the suggested method changes templates after each completion of authentication, and thus the compromised templates cannot be reused. Furthermore, a huge number of chaff minutiae can be added by expanding the size of the fingerprint image. Therefore, the proposed method can protect a user's fingerprint minutiae against the correlation attack. In our experiments, the proposed approach can improve the security level of a typical approach against brute-force attack by the factor of $10^{34}$.

• ETRI Journal
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• v.31 no.5
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• pp.628-630
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• 2009

Recently, Ratha and others proposed a cancelable biometrics scheme which transforms an original fingerprint template into a new one using a noninvertible transformation. However, we show that the original template is recovered by a dictionary attack if two transformed templates originating from it are revealed. In our attack, we simulate the transformation and construct a set of possible pre-images for each transformed template. Then, we find the correct pre-image by computing the intersection of these sets. We present an algorithm implementing this idea as well as successful experimental results.

• Nuclear Engineering and Technology
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• v.52 no.5
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• pp.995-1001
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• 2020

With the development of digital instrumentation and control (I&C) devices, cyber security at nuclear power plants (NPPs) has become a hot issue. The Stuxnet, which destroyed Iran's uranium enrichment facility in 2010, suggests that NPPs could even lead to an accident involving the release of radioactive materials cyber-attacks. However, cyber security research on industrial control systems (ICSs) and supervisory control and data acquisition (SCADA) systems is relatively inadequate compared to information technology (IT) and further it is difficult to study cyber-attack taxonomy for NPPs considering the characteristics of ICSs. The advanced research of cyber-attack taxonomy does not reflect the architectural and inherent characteristics of NPPs and lacks a systematic countermeasure strategy. Therefore, it is necessary to more systematically check the consistency of operators and regulators related to cyber security, as in regulatory guide 5.71 (RG.5.71) and regulatory standard 015 (RS.015). For this reason, this paper attempts to suggest a template for cyber-attack taxonomy based on the characteristics of NPPs and exemplifies a specific cyber-attack case in the template. In addition, this paper proposes a systematic countermeasure strategy by matching the countermeasure with critical digital assets (CDAs). The cyber-attack cases investigated using the proposed cyber-attack taxonomy can be used as data for evaluation and validation of cyber security conformance for digital devices to be applied, and as effective prevention and mitigation for cyber-attacks of NPPs.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.4
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• pp.2237-2253
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• 2017

For the existing security problem based on Fuzzy Vault algorithm, we propose a cancelable fingerprint template encryption scheme in this paper. The main idea is to firstly construct an irreversible transformation function, and then apply the function to transform the original template and template information is stored after conversion. Experimental results show it effectively prevents the attack from fingerprint template data and improves security of the system by using minutiae descriptor to encrypt abscissa of the vault. The experiment uses public FVC2004 fingerprint database to test, result shows that although the recognition rate of the proposed algorithm is slightly lower than the original program, but the improved algorithm security and complexity are better, and therefore the proposed algorithm is feasible in general.

• Journal of KIISE:Computing Practices and Letters
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• v.9 no.3
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• pp.341-351
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• 2003

Digital image watermarking is the method that can protect the copyright of the image by embedding copyright information, which is called watermark. Watermarking must have robustness to intentional or unintentional data changing, called attack. The conventional watermarking schemes are robust to waveform attacks such as image compression, filtering etc. However, they are vulnerable to geometrical attacks such as rotation, scaling, translation, and cropping. Accordingly, this paper proposes new watermarking scheme that is robust to geometrical attacks by using invariant centroid. Invariant centroid is the gravity center of a central area in a gray scale image that remains unchanged even when the image is attacked by RST including cropping and proposed scheme uses invariant centroids of original and inverted image as the template. To make geometrically invariant domain, template and angle compensated Log -Polar Map(LPM) is used. Then Discrete Cosine Transform(DCT) is performed and the watermark is embedded into the DCT coefficients. Futhermore, to prevent a watermarked image from degrading due to interpolation during coordinate system conversion, only the image of the watermark signal is extracted and added to the original image. Experimental results show that the proposed scheme is especially robust to RST attacks including cropping.

• Proceedings of the IEEK Conference
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• 2001.09a
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• pp.201-204
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• 2001

워터마크(watermarks)는 원데이터에 크게 손상을 주지 않으면서도 필요한 정보를 숨겨서 삽입하여야 하며, 압축이나 포맷변환 또는 의도적인 공격에 대하여 강인하게 검출되어야 한다. 본 논문에서는 템플릿(template)을 이용하여 압축이나 필터링 등의 일반적인 영상처리 뿐만 아니라, 회전(rotation), 확대 및 축소(scale), 평행이동(translation) 등과 같은 기하학적 변환(geometric attack)에 대해서도 강인한 워터마크 기법을 제안한다. 본 알고리듬은 템플릿을 웨이블릿(wavelet) 공간의 모든 대역에 삽입하여 강인한 템플릿을 구성한다. 템플릿을 이용한 강인한 워터마크 기법은 영상 압축 및 기하학적 변환에 대하여 우수한 성능을 보였다.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.4
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• pp.437-444
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• 2008

This paper deals with the biometric template protection in the biometric system which has been widely used for personal authentication. First, we consider the structure of the biometric system and the function of its sub-systems and define the biometric template and identification(ID) information. And then, we describe the biometric template attack points of a biometric system and attack examples and provide their countermeasures. From this, we classify the vulnerability which can be protected by encryption and hashing techniques. For more detail investigation of these at real operating situations, we analyze them and suggest several protection methods for the typical application scheme of biometric systems such as local model, download model, attached model, and center model. Finally, we also handle the privacy problem which is most controversy issue related to the biometric systems and suggest some guidances of safeguarding procedures on establishing privacy sympathy biometric systems.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.2
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• pp.13-25
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• 2011

Biometric-based authentication can provide strong security guarantee about the identity of users. However, security of biometric data is particularly important as the compromise of the data will be permanent. The fuzzy fingerprint vault system is one of the most popular solutions for protecting the fingerprint template stored in the database. Recently, however, this system is very susceptible to a correlation attack that finds the real minutiae using multiple fingerprint vaults enrolled for different applications. To solve this problem, we propose a robust fuzzy fingerprint vault system against the correlation attack. In this paper, we add chaff minutiae based on the relative information of minutiae such as direction, coordinate instead of adding randomly. Also, our proposed approach allow to add multiple chaff minutiae within tolerance box for enhanced security level. Experimental results show that the proposed approach can protect the correlation attack and achieve enhanced verification accuracy.