• KIPS Transactions on Computer and Communication Systems
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• v.9 no.5
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• pp.107-112
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• 2020

Ultra-lightweight password CHAM is an algorithm with efficient addition, rotation and XOR operations on resource constrained devices. CHAM shows high computational performance, especially on IoT platforms. However, lightweight block encryption algorithms used on the Internet of Things may be vulnerable to side channel analysis. In this paper, we demonstrate the vulnerability to side channel attack by attempting a first power analysis attack against CHAM. In addition, a safe algorithm was proposed and implemented by applying a masking technique to safely defend the attack. This implementation implements an efficient and secure CHAM block cipher using the instruction set of an 8-bit AVR processor.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.2
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• pp.449-456
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• 2015

Recently, information security of IoT(Internet of Things) have been increasing to interest and many research groups have been studying for cryptographic algorithms, which are suitable for IoT environment. LEA(Lightweight Encryption Algorithm) developed by NSRI(National Security Research Institute) is commensurate with IoT. In this paper, we propose two first-order Correlation Power Analysis(CPA) attacks for LEA and experimentally demonstrate our attacks. Additionally, we suggest the mask countermeasure for LEA defeating our attacks. In order to estimate efficiency for the masked LEA, its operation cost is compared to operation time of masked AES.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.221-223
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• 2014

Power analysis attack on cryptographic hardware device aims to study the power consumption while performing operations using secrets keys. Power analysis is a form of side channel attack which allow an attacker to compute the key encryption from algorithm using Simple Power Analysis (SPA), Differential Power Analysis (DPA) or Correlation Power Analysis (CPA). The theoretical weaknesses in algorithms or leaked informations from physical implementation of a cryptosystem are usually used to break the system. This paper describes how power analysis work and we provide an overview of countermeasures against power analysis attacks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.9B
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• pp.1369-1380
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• 2010

In this paper, we propose the efficient Second-Order Differential Power Analysis attack, which has ability to find significant information such as secret key in the devices consisting IT convergence environment such as Smartgrid, Advanced Metering Infrastructure(AMI) and ZigBee-based home networking service. This method helps to find the secret key easily at a device, even though it uses a countermeasure like masking which makes First-Order DPA attack harder. First, we present the performance results of our implementation which implements practical Second-Order DPA attack using the existing preprocessing function, and analyze it. Then we propose a stronger preprocessing function which overcomes countermeasures like masking. Finally, we analyze the results of the Second-Order CPA attack using proposed preprocessing function and verify that proposed scheme is very threatening to the security fields of IT convergence technology through the experimental results.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.2
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• pp.151-164
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• 2023

Recently, the development of quantum computers means a great threat to existing public key system based on discrete algebra problems or factorization problems. Accordingly, NIST is currently in the process of contesting and screening PQC(Post Quantum Cryptography) that can be implemented in both the computing environment and the upcoming quantum computing environment. Among them, SIKE is the only Isogeny-based cipher and has the advantage of a shorter public key compared to other PQC with the same safety. However, like conventional cryptographic algorithms, all quantum-resistant ciphers must be safe for existing cryptanlysis. In this paper, we studied power analysis-based cryptographic analysis techniques for SIKE, and notably we analyzed SIKE through wavelet transformation and deep learning-based clustering power analysis. As a result, the analysis success rate was close to 100% even in SIKE with applied masking response techniques that defend the accuracy of existing clustering power analysis techniques to around 50%, and it was confirmed that was the strongest attack on SIKE.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.2
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• pp.287-297
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• 2019

When cryptographic algorithms are implemented to provide countermeasures against the side-channel analysis, designers frequently employ the combined countermeasures between the first-order masking scheme and hiding schemes. Their combination can be enough to offer security and efficiency. However, if dummy operations can be distinguished from real operations, an attacker can extract the secret key with lower complexity than the intended attack complexity by the designer inserting the dummy operations. In this paper, we categorize types of variables used in a dummy operation when C language is employed. Then, we present the novel vulnerability that can distinguish dummy operations for all cases where the hiding schemes are applied using different types of variables. Moreover, the countermeasure is provided to prevent the novel vulnerability.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.9
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• pp.393-398
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• 2013

This paper introduces a new collision attack on first-order masked AES. This attack is a known plaintext attack, while the existing collision attacks are a chosen plaintext attack. In addition, our method is more efficient than the second-order power analysis and requires about 1/27.5 power measurements by comparison with the last collision attack. Some experiment results of this paper support this fact. In this paper, we also introduce a simple countermeasure, which can protect against our attack.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.4
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• pp.803-807
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• 2018

The Fantomas and the Robin are the block ciphers included in the LS-designs, the family of block ciphers. They are designed to efficiently apply the masking technique, which is a side-channel analysis countermeasure technique, using L-boxes and S-boxes capable of bit slice implementation. In this paper, we show that the key recovery attacks of Fantomas and Robin through the related-key differential analysis are possible with $2^{56}$ and $2^{72}$ time complexity, $2^{56}$ and $2^{69}$ chosen plaintext respectively.

• Journal of Environmental Health Sciences
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• v.24 no.1
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• pp.62-69
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• 1998

It has been studied that the measurement of odor component emission at confectionery manufacture. The objects of this study were to investigate reduction of offensive odor. The survey effects of odorous materials are presented as follows. The countermeasure of operating process is to minimize sludge sediment in each unit facility. Especially, in summer, we have to clean the sludge frequently, because anaerobic decomposing is likely to occur easily. The sludge or scum from sedimentation tank pond, and floating tank should be treated quickly. We should avoid overloading operation. In the case of overloading, dissolved oxygen should be increased, the quality of wastewater input should be decreased. When dried cakes from condense tank or floating tank are left in treatment plant, we should cover, to prevent diffusion of smell with masking materials. The seasonal condition of operating should be fixed and the kind of coagulants should be changed because the wastewater in each season have different loading rates and organic materials. Odorous materials are very sensitive to the seasonal temperature variation. Especially, when the amount of rainfall is small and the high temperature of maintenance in long periods, air diffusion rate is large, so odorous materials can make great effect on surroundings comparision with other periods. To reduce odorous gas, as short term method, we had better take ceramic addition method. Especially, in summer we should take ceramic addition method. Also, as long term method, the size of wastewater treatment facility is the most important in the normal operating of wastewater treatment facility. But wastewater treatment facilities in this factory are too old, treatment process is old fashion, and the size is too small. So, large wastewater quantity to treat in summer. As results, the expansion of wastewater treatment facility and the process of improvement are required. Restriction level of odor was exceed. As it is overloaded in summer, the basis cause of odor is that the size of wastewater treatment facility is small. The prediction of air quality equilibrium density variation show that the odorous materials from working place are Amine materials whose smell strength is about 2.5(a little strong degree). We can suppose that in summer is sensitive to temperature variation, smell strength is larger as to reduce the origin of odor. We must expand wastewater treatment facility and improve the process A.S.A.P.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.11
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• pp.8-15
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• 2009

Side-channel attacks including the differential power analysis attack are often more powerful than classical cryptanalysis and have to be seriously considered by cryptographic algorithm's implementers. Various countermeasures have been proposed against such attacks. In this paper, we deal with the masking method, which is known to be a very effective countermeasure against the differential power analysis attack and propose new gate-level conversion methods between Boolean and arithmetic masks. The new methods require only 6n-5 XOR and 2n-2 AND gates with 3n-2 gate delay for converting n-bit masks. The basic idea of the proposed methods is that the carry and the sum bits in the ripple adder are manipulated in a way that the adversary cannot detect the relation between these bits and the original raw data. Since the proposed methods use only bitwise operations, they are especially useful for DPA-securely implementing cryptographic algorithms in hardware which use both Boolean and arithmetic operations. For example, we applied them to securely implement the block encryption algorithm SEED in hardware and present its detailed implementation result.