• KIPS Transactions on Computer and Communication Systems
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• v.4 no.3
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• pp.105-108
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• 2015

In this paper, we propose a differential fault analysis on symmetric SPN block cipher with bitslice involution S-box in 2011. The target block cipher was designed using AES block cipher and has advantage about restricted hardware and software environment using the same structure in encryption and decryption. Therefore, the target block cipher must be secure for the side-channel attacks. However, to recover the 128-bit secret key of the targer block cipher, this attack requires only one random byte fault and an exhausted search of $2^8$. This is the first known cryptanalytic result on the target block cipher.

• KIPS Transactions on Computer and Communication Systems
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• v.5 no.12
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• pp.481-490
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• 2016

Bluetooth utilizes a symmetric key that is exchanged at the first pairing to establish a secure channel. There are four authentication modes which enables device authentication, Just work, Passkey Entry, Out of Band, and Numeric Comparison. Up to now, Just work has been considered as the authentication mode that is vulnerable to Man-In-The-Middle (MITM) Attack. In addition, it is possible to intentionally change any authentication mode to Just work mode, in order to succeed in MITM Attack under Just work mode. However, this kind of attacks have just worked under the assumption that users should not notice that authentication mode was changed. In this paper, We analyze the specification of Secure Simple Pairing, LE Legacy Pairing and LE Secure Connection Pairing. When using Passkey Entry mode on each approach, it seems the MITM attack is possible. Also it offers Passkey Entry MITM attack that does not require assumptions about the user's fault, because it isn't change verification process of the authentication mode unlike traditional attacks. We implement the proposed MITM attacks. Also we presents a scenario in which an attack can be exploited and a countermeasure.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.3
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• pp.477-489
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• 2014

Based on some flaws occurred for implementing a public key cryptosystem in the embedded security device, many side-channel attacks to extract the secret private key have been tried. In spite of the fact that the cryptographic exponentiation is basically composed of a sequence of multiplications and squarings, a new Square Always exponentiation algorithm was recently presented as a countermeasure against side-channel attacks based on trading multiplications for squarings. In this paper, we propose Known Power Collision Analysis and modified Doubling attacks to break the Right-to-Left Square Always exponentiation algorithm which is known resistant to the existing side-channel attacks. And we also present a Collision-based Combined Attack which is a combinational method of fault attack and power collision analysis. Furthermore, we verify that the Square Always algorithm is vulnerable to the proposed side-channel attacks using computer simulation.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.406-410
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• 2010

Current paper represents the air data acquisition and processing algorithm which can acquire the air data such as velocity and angle of attack by measuring the static pressure on the specific locations of a high speed aerial vehicle. Unlike the previous air data acquisition system, current system applied several pre-determined data obtained from computational fluid dynamic approach having enough sensor redundancy and fault detection ability. The verification of current algorithm was done by commercial software Matlab and Simulink.

• Journal of Electrical Engineering and Technology
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• v.9 no.3
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• pp.1043-1050
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• 2014

Obsolescent control systems for power systems are evolving into intelligent systems and connecting with smart devices to give intelligence to the power systems. As networks of the control system are growing, vulnerability is also increasing. The communication network of distribution areas in the power system connects closely to vulnerable environments. Many cyber-attacks have been founded in the power system, and they could be more critical as the power system becomes more intelligent. From these environment, new communication network architecture and mitigation method against cyber-attacks are needed. Availability and Fault Tree analysis used to show that the proposed system enhances performance of current control systems.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2003.12a
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• pp.141-145
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• 2003

We propose the model of Software Rejuvenation methodology, which is applicable for survivability. Software rejuvenation is a proactive fault management technique and being used in fault tolerant systems as a cost effective technique for dealing with software faults. Survivability focuses on delivery of essential services and preservation of essential assets, even systems are penetrated and compromised. Thus, our objective is to detect the intrusions in a real time and survive in face of such attacks. As we deterrent against an attack in a system level, the Intrusion tolerance could be maximized at the target environment. We address the optimal time to execute ad hoc software rejuvenation and we compute it by using the semi Markov process. This is one way that could be really frustrated and deterred the attacks, as the attacker can't make their progress. This Software Rejuvenation method can be very effective under the assumption of unknown attacks. In this paper, we compute the optimum time to perform an ad hoc Software Rejuvenation through intrusions.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2003.12a
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• pp.39-44
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• 2003

오류분석 공격은 암호시스템에 오류를 주입한 후 그 출력 결과를 분석하여 비밀키를 찾아내는 물리적 공격 방법으로서 RSA, ECC를 포함한 공개 키 시스템을 비롯하여 DES, AES와 같은 대칭 키 암호시스템에도 공격이 시도되고 있다. 본 논문에서는 기존 DES 공격에 사용된 오류 주입의 가정만 있으면 국내 표준 블록 암호 알고리듬인 SEED 역시 오류 주입 공격이 가능함을 증명한다. 또한, 오류 주입 공격에 의해 SEED의 라운드 키 두개만 공격되면 원 암호 키가 모두 노출될 수 있음을 검증한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.732-742
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• 2016

This study suggests methods of defense against low-level high-bandwidth DDoS attacks by adding a solution with a time limit factor (TLF) to an existing high-bandwidth DDoS defense system. Low-level DDoS attacks cause faults to the service requests of normal users by acting as a normal service connection and continuously positioning the connected session. Considering this, the proposed method makes it possible for users to show a down-related session by considering it as a low-level DDoS attack if the abnormal flow is detected after checking the amount of traffic. However, the service might be blocked when misjudging a low-level DDoS attack in the case of a communication fault resulting from a network fault, even with a normal connection status. Thus, we made it possible to reaccess the related information through a certain period of blocking instead of a drop through blacklist. In a test of the system, it was unable to block the session because it recognized sessions that are simply connected with a low-level DDoS attack as a normal communication.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.1
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• pp.536-551
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• 2017

With the advancement and deployment of leading-edge telecommunication technologies for sensing and collecting, computing related information, Cloud of Things (CoTs) has emerged as a typical application platform that is envisioned to revolutionize the daily activities of human society, such as intelligent transportation, modern logistics, food safety, environmental monitoring, etc. To avoid any possible malicious attack and resource abuse, employing hash functions is widely recognized as one of the most effective approaches for CoTs to achieve message integrity and data authentication. The Whirlpool hash function has served as part of the joint ISO/IEC 10118-3 International Standard by the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC). In this paper, we propose an effective differential fault analysis on Whirlpool in the byte-oriented random fault model. The mathematical analysis and experimental results show that 8 random faults on average are required to obtain the current 512-bit message input of whirlpool and the secret key of HMAC-Whirlpool. Our work demonstrates that Whirlpool and HMAC-Whirlpool are both vulnerable to the single byte differential fault analysis. It provides a new reference for the security analysis of the same structure of the hash functions in the CoTs.

• Journal of KIISE:Computer Systems and Theory
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• v.36 no.1
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• pp.33-39
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• 2009

This paper presents a new secure scan design technique to protect secret key from scan-based side channel attack for an Advanced Encryption Standard(AES) core embedded on an System-on-a-Chip(SoC). Our proposed secure scan design technique can be applied to crypto IF core which is optimized for applications without the IP core modification. The IEEE1149.1 standard is kept, and low area and power consumption overheads and high fault coverage can be achieved compared to the existing methods.