• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.5
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• pp.1094-1107
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• 2013

NTRU cryptosystem has been suggested for protecting wireless body area networks, which is secure in the sense of traditional cryptanalysis. In this paper, we fulfill the first power analysis attack on the ultra-low-power environment of wireless body area networks. Specifically, two practical differential power analyses on NTRU algorithm are proposed, which can attack the existing countermeasures of NTRU. Accordingly, we suggest three countermeasures against our attacks. Meanwhile, practical experiments show that although the attacks in this paper are efficient, our countermeasures can resist them effectively.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.1
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• pp.261-269
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• 2014

There are many researches on fast exponentiation algorithm which is used to implement a public key cryptosystem such as RSA. On the other hand, the malicious attacker has tried various side-channel attacks to extract the secret key. In these attacks, an attacker uses the power consumption or electromagnetic radiation of cryptographic devices which is measured during computation of exponentiation algorithm. In this paper, we propose a novel simple power analysis attack on m-ary exponentiation implementation. The core idea of our attack on m-ary exponentiation with pre-computation process is that an attacker controls the input message to identify the power consumption patterns which are related with secret key. Furthermore, we implement the m-ary exponentiation on evaluation board and apply our simple power analysis attack to it. As a result, we verify that the secret key can be revealed in experimental environment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.9B
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• pp.1330-1341
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• 2010

Power analysis (PA) is known as a powerful physical attack method in the field of information security. This method uses the statistical characteristics of leaked power consumption signals measured from security devices to reveal the secret keys. However, when measuring a leakage power signal, it may be easily distorted by the noise due to its low magnitude values, and thus the PA attack shows different performances depending on the noise level of the measured signal. To overcome this vulnerability of the PA attack, we propose a noise-reduction method based on wavelet de-noising. Experimental results show that the proposed de-noising method improves the attack efficiency in terms of the number of signals required for the successful attack as well as the reliability on the guessing key.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.6
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• pp.1091-1102
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• 2014

The power analysis attack is a cryptanalytic technique to retrieve an user's secret key using the side-channel power leakage occurred during the execution of cryptographic algorithm embedded on a physical device. Especially, many power analysis attacks have targeted on an exponentiation algorithm which is composed of hundreds of squarings and multiplications and adopted in public key cryptosystem such as RSA. Recently, a new correlation power attack, which is tried when two modular multiplications have a same input, is proposed in order to recover secret key. In this paper, after reviewing the principle of side-channel attack based on input collisions in modular multiplications, we analyze the vulnerability of some exponentiation algorithms having regularity property. Furthermore, we present an improved exponentiation countermeasure to resist against the input collision-based CPA(Correlation Power Analysis) attack and existing side channel attacks and compare its security with other countermeasures.

• Proceedings of the KIEE Conference
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• 2007.11b
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• pp.294-295
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• 2007

The importance of security is increased in power industry. Recently Power IT networks are attacked in cyber space and demage of attack become increased. For solving the problems, many research studies for network security enhancement are globally carried out in the world. In this paper, we introduce recent cyber attack cases, efforts for enhancing cyber safeness and put into perspective of potential security areas for power IT areas.

• 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.

• Nuclear Engineering and Technology
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• v.49 no.3
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• pp.484-494
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• 2017

In industrial plants such as nuclear power plants, system operations are performed by embedded controllers orchestrated by Supervisory Control and Data Acquisition (SCADA) software. A targeted attack (also termed a control aware attack) on the controller/SCADA software can lead a control system to operate in an unsafe mode or sometimes to complete shutdown of the plant. Such malware attacks can result in tremendous cost to the organization for recovery, cleanup, and maintenance activity. SCADA systems in operational mode generate huge log files. These files are useful in analysis of the plant behavior and diagnostics during an ongoing attack. However, they are bulky and difficult for manual inspection. Data mining techniques such as least squares approximation and computational methods can be used in the analysis of logs and to take proactive actions when required. This paper explores methodologies and algorithms so as to develop an effective monitoring scheme against control aware cyber attacks. It also explains soft computation techniques such as the computational geometric method and least squares approximation that can be effective in monitor design. This paper provides insights into diagnostic monitoring of its effectiveness by attack simulations on a four-tank model and using computation techniques to diagnose it. Cyber security of instrumentation and control systems used in nuclear power plants is of paramount importance and hence could be a possible target of such applications.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.3
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• pp.1802-1819
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• 2017

Correlation-enhanced collision attack has been proposed by Moradi et al. for several years. However, in practical operations, this method costs lots of time on trace acquisition, storage and averaging due to its bytewise collision detection. In this paper, we propose a bitwise collision attack based on second-order distance model. In this method, only 9 average traces are enough to finish a collision attack. Furthermore, two candidate models are given in this study to distinguish collisions, and the corresponding practical experiments are also performed. The experimental results indicate that the operation time of our attack is only 8% of that of correlation-enhanced collision attack, when the two success rates are both above 0.9.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.19 no.1
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• pp.43-51
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• 2009

In 1998, Kocher et al. introduced Differential Power Attack on block ciphers. This attack allows to extract secret key used in cryptographic primitives even if these are executed inside tamper-resistant devices such as smart card. At FSE 2003 and 2004, Akkar and Goubin presented several masking methods, randomizing the first few and last few($3{\sim}4$) rounds of the cipher with independent random masks at each round and thereby disabling power attacks on subsequent inner rounds, to protect iterated block ciphers such as DES against Differential Power Attack. Since then, Handschuh and Preneel have shown how to attack Akkar's masking method using Differential Cryptanalysis. This paper presents how to combine Truncated Differential Cryptanalysis and Power Attack to extract the secret key from intermediate unmasked values and shows how much more efficient our attacks are implemented than the Handschuh-Preneel method in term of reducing the number of required plaintexts, even if some errors of Hamming weights occur when they are measured.

• Convergence Security Journal
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• v.18 no.1
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• pp.117-128
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• 2018

The purpose of this paper is to analyze the behavior of North Korea's cyber attack against South Korea since 2009 based on major international security theories and suggest South Korea's policy option. For this purpose, this paper applied the behavioral domain and characteristics of 'cyber power' and 'coercion dynamics' model, which are attracting attention in international security studies. The types of cyber attacks from North Korea are classified into the following categories: power-based incarceration, leadership attacks and intrusions, military operations interference, and social anxiety and confusion. In terms of types and means of cyber power, North Korean GPS disturbance, the Ministry of Defense server hacking and EMP are hard power with high retaliation and threat and cyber money cashing and ransomware are analyzed by force in the act of persuasion and incentive in the point of robbing or asking for a large amount of money with software pawns. North Korea 's cyber attack has the character of escape from realistic sanctions based on the second nuclear test. It is important for South Korea to clearly recognize that the aggressive cyberpower of North Korea is changing in its methods and capabilities, and to ensure that North Korea's actions result in far greater losses than can be achieved. To do this, it is necessary to strengthen the cyber security and competence to simultaneously attack and defend through institutional supplement and new establishment such as cyber psychological warfare, EMP attack preparation, and enhancement of security expertise against hacking.