• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.4
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• pp.727-738
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• 2015

Until recently, power analysis is one of the most popular research issues among various side channel analyses. Since Differential Power Analysis had been first proposed by Kocher et al., various practical power analyses correspond with software/hardware cryptographic devices have been proposed. In this paper, we analyze vulnerability of countermeasure against power analysis exploiting single power trace of public cryptographic algorithm. In ICICS 2010, Clavier et al. proposed Horizontal Correlation Analysis which can recover secret information from a single exponentiation trace and corresponding countermeasures. "Blind operands in LIM", one of their countermeasures, exploits additive blinding in order to prevent leakage of intermediate value related to secret information. However, this countermeasure has vulnerability of having power leakage that is dependant with the message known by an adversary. In this paper, we analyzed vulnerabilities by three attack scenarios and proved them by practical correlation power analysis experiments.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.5
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• pp.14-21
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• 2020

In order to provide confidential services between two communicating parties, block data encryption using a symmetric secret key is applied. A power analysis attack on a cryptosystem is a side channel-analysis method that can extract a secret key by measuring the power consumption traces of the crypto device. In this paper, we propose an attack model that can recover the secret key using a power analysis attack based on a deep learning convolutional neural network (CNN) algorithm. Considering that the CNN algorithm is suitable for image analysis, we particularly adopt the recurrence plot (RP) signal processing method, which transforms the one-dimensional power trace into two-dimensional data. As a result of executing the proposed CNN attack model on an XMEGA128 experimental board that implemented the AES-128 encryption algorithm, we recovered the secret key with 22.23% accuracy using raw power consumption traces, and obtained 97.93% accuracy using power traces on which we applied the RP processing method.

• ETRI Journal
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• v.32 no.3
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• pp.362-369
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• 2010

While the elliptic curve cryptosystem (ECC) is getting more popular in securing numerous systems, implementations without consideration for side-channel attacks are susceptible to critical information leakage. This paper proposes new power attack countermeasures for ECC over Koblitz curves. Based on some special properties of Koblitz curves, the proposed methods randomize the involved elliptic curve points in a highly regular manner so the resulting scalar multiplication algorithms can defeat the simple power analysis attack and the differential power analysis attack simultaneously. Compared with the previous countermeasures, the new methods are also noticeable in terms of computational cost.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.5
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• pp.1089-1098
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• 2018

As the development of quantum computers becomes visible, the researches on post-quantum cryptography to alternate the present cryptography system have actively pursued. To substitute RSA and Elliptic Curve Cryptosystem, post-quantum cryptography must also consider side channel resistance in implementation. In this paper, we propose a side channel analysis on NTRU, based on the implementation made public in the NIST standardization. Unlike the previous analysis which exploits a thousands of traces, the proposed attack can recover the private key using a single power consumption trace. Our attack not only reduces the complexity of the attack but also gives more possibility to analyze a practical public key cryptosystem. Furthermore, we suggested the countermeasure against our attacks. Our countermeasure is much more efficient than existing implementation.

• ETRI Journal
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• v.34 no.1
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• pp.76-86
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• 2012

The block cipher ARIA has been threatened by side-channel analysis, and much research on countermeasures of this attack has also been produced. However, studies on countermeasures of ARIA are focused on software implementation, and there are no reports about hardware designs and their performance evaluation. Therefore, this article presents an advanced masking algorithm which is strong against second-order differential power analysis (SODPA) and implements a secure ARIA hardware. As there is no comparable report, the proposed masking algorithm used in our hardware module is evaluated using a comparison result of software implementations. Furthermore, we implement the proposed algorithm in three types of hardware architectures and compare them. The smallest module is 10,740 gates in size and consumes an average of 47.47 ${\mu}W$ in power consumption. Finally, we make ASIC chips with the proposed design, and then perform security verification. As a result, the proposed module is small, energy efficient, and secure against SODPA.

• Journal of Communications and Networks
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• v.11 no.6
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• pp.556-563
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• 2009

A side channel analysis is a very efficient attack against small devices such as smart cards and wireless sensor nodes. In this paper, we propose an efficient key detection method using a peak selection algorithm in order to find the advanced encryption standard secret key from electromagnetic signals. The proposed method is applied to a correlation electromagnetic analysis (CEMA) attack against a wireless sensor node. Our approach results in increase in the correlation coefficient in comparison with the general CEMA. The experimental results show that the proposed method can efficiently and reliably uncover the entire 128-bit key with a small number of traces, whereas some extant methods can reveal only partial subkeys by using a large number of traces in the same conditions.

• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.443-450
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• 2017

Nowadays, Power Line Communication (PLC) is gaining high attention from industry and electric supply companies for the services like demand response, demand side management and Advanced Metering Infrastructure (AMI). The reliable services to consumers using PLC can be provided by utilizing an efficient PLC channel for which sophisticated channel modeling is very important. This paper presents characterization of a Low Voltage (LV) access network for Narrowband Power Line Communications (NB-PLC) using transmission line (TL) theory and a Simulink model. The TL theory analysis not only includes the constant parameters but frequency selectivity is also introduced in these parameters such as resistance, conductance and impedances. However, the proposed Simulink channel model offers an analysis and characterization of capacitive coupler, network impedance and channel transfer function for NB-PLC. Analysis of analytical and simulated results shows a close agreement of the channel transfer function. In the absence of a standardized NBPLC channel model, this research work can prove significant in improving the efficiency and accuracy of NB-PLC communication transceivers for Smart Grid communications.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.19 no.3
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• pp.27-35
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• 2009

Differential Power Analysis (DPA) based on the statistical characteristics of collected signals has been known as an efficient attack for uncovering secret key of crypto-systems. However, the attack performance of this method is affected very much by the temporal misalignment and the noise of collected side channel signals. In this paper, we propose a new method based on wavelet analysis to surmount the temporal misalignment and the noise problem simultaneously in DPA. The performance of the proposed method is then evaluated while analyzing the power consumption signals of Micro-controller chips during a DES operation. The experimental results show that our proposed method based on wavelet analysis requires only 25% traces compared with those of the previous preprocessing methods to uncover the secret key.

• International Journal of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.17-28
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• 2024

As listed as one of the most important requirements for Post-Quantum Cryptography standardization process by National Institute of Standards and Technology, the resistance to various side-channel attacks is considered very critical in deploying cryptosystems in practice. In fact, cryptosystems can easily be broken by side-channel attacks, even though they are considered to be secure in the mathematical point of view. The timing attack(TA) and the simple power analysis attack(SPA) are such side-channel attack methods which can reveal sensitive information by analyzing the timing behavior or the power consumption pattern of cryptographic operations. Thus, appropriate measures against such attacks must carefully be considered in the early stage of cryptosystem's implementation process. The Montgomery multiplier is a commonly used and classical gadget in implementing big-number-based cryptosystems including RSA and ECC. And, as recently proposed as an alternative of building blocks for implementing post quantum cryptography such as lattice-based cryptography, the big-number multiplier including the Montgomery multiplier still plays a role in modern cryptography. However, in spite of its effectiveness and wide-adoption, the multiplier is known to be vulnerable to TA and SPA. And this paper proposes a new countermeasure for the Montgomery multiplier against TA and SPA. Briefly speaking, the new measure first represents a multiplication operand without 0 digits, so the resulting multiplication operation behaves in a very regular manner. Also, the new algorithm removes the extra final reduction (which is intrinsic to the modular multiplication) to make the resulting multiplier more timing-independent. Consequently, the resulting multiplier operates in constant time so that it totally removes any TA and SPA vulnerabilities. Since the proposed method can process multi bits at a time, implementers can also trade-off the performance with the resource usage to get desirable implementation characteristics.

• 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.