• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.5
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• pp.765-777
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• 2022

The SABER algorithm, a PKE/KEM algorithm presented in NIST PQC Standardization Round 3, is an algorithm based on the Module-LWR problem among lattice-based problems and has a Meta-PKE structure. At this time, the secret information used in the encryption process is called a ephemeral key, and in this paper, the ephemeral key reuse attack using the Meta-PKE structure is described. For each parameter satisfying the security strengths required by NIST, we present a detailed analysis of the previous studies attacked using 4, 6, and 6 queries, and improve them, using only 3, 4, and 4 queries. In addition, we introduce how to reduce the computational complexity of recovering ephemeral keys with a single query from the brute-force complexity on the n-dimension lattice, 2^7.91×n, 2^10.51×n, 2^12.22×n to 2^4.91×n, 2^6.5×n, 2^6.22×n, for each parameter, and present the results and limitations.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.2
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• pp.335-344
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• 2016

It is known that power analysis is one of the most powerful attack in side channel analysis. Among power analysis single trace attack is widely studied recently since it uses one power consumption trace to recover secret key of public cryptosystem. Recently Sim et al. proposed new exponentiation algorithm for RSA cryptosystem with higher attack complexity to prevent single trace attack. In this paper we analyze the vulnerability of exponentiation algorithm described by Sim et al. Sim et al. applied message blinding and random exponentiation splitting method on $2^t-ary$ for higher attack complexity. However we can reveal private key using information exposed during pre-computation generation. Also we describe modified algorithm that provides higher attack complexity on collision attack. Proposed algorithm minimized the reuse of value that are used during exponentiation to provide security under single collision attack.

• Journal of the Korea Society of Computer and Information
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• v.14 no.1
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• pp.107-115
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• 2009

The cryptological key which is used in WiMAX environment is used at regular intervals by mobile nodes (laptop computer, PDA, cell-phone) which is in the range of base station coverage. But it is very weak at local attack like man-in-the-middle when the mobile node is off the range of base station or enters into the range to communicate with base station because the communication section is activated wirelessly. This paper proposes a distribution key building protocol which can reuse security key used by nodes to reduce cryptological security attack danger and communication overhead which occurs when mobile node tries to communicate with base station. The proposed distribution key establishing protocol can reduce overhead which occurs between base station and mobile node through key reusing which occurs during the communication process and also, makes security better than IEEE 802.16 standard by creating shared key which is required for inter-certification through the random number which node itself creates.

• The KIPS Transactions:PartC
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• v.11C no.4
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• pp.497-508
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• 2004

The existing wireless LAN standard IEEE802.11b has many vulnerabilities from security point of view. The authentication mechanisms in IEEE802.11b have many vulnerabilities. As a result to complement the weak of IEEE802.11b authentication, the IEEE802.1x had been developed in the sense of providing strong user authentication with appropriate mechanism. But this mechanism does not perform AP authentication and there are also some weak points. And in confidentiality and message Integrity case, WEP is weak from key stream reuse attack, IV reuse attack and so on. For that reason, in this paper we propose secure wireless LAN system. Our system provides strong user authentication, confidentiality, and message integrity based on existing IEEE802.1x framework and TLS.

• Proceedings of the Korean Society of Computer Information Conference
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• 2019.01a
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• pp.361-363
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• 2019

인터넷환경에서 금융회사는 홈페이지 사용자의 신원확인, 부인방지 등의 목적으로 공개키 기반구조(PKI: Public Key Infrastructure) 환경의 공인인증서를 홈페이지 로그인, 전자금융거래 등의 업무에 적용하고 있다. 사용자의 공인인증서를 이용하여 생성된 전자서명이 악성코드 감염 등으로 인하여 유출 시 사용자가 과거에 서명했던 전자서명이 재사용(로그인, 전자금융거래 등)될 수 있는 취약점이 존재하기에 인터넷 상에서의 전자서명 재사용에 대한 원인, 방지 절차 및 방법을 제안 하고자 한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.11B
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• pp.1005-1016
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• 2006

As the increment usage of Internet, the security systems's importance is emphasized. The current Internet Key Exchange protocol(IKE) which has been used for key exchange of security system, was pointed out a problem of efficiency and stability. In this research, we try to resolve those problems, and evaluate the newly designed Key Exchange protocol in the IPsec interaction test bed system environment. In this research we implemented the new Key Exchange Protocol as a recommendation of RFC proposal, so as to resolve the problem which was pointed out the key exchange complexity and the speed of authentication process. We also designed the defense mechanism against the Denial of Service attack. We improved the key exchange speed as a result of simplification of complex key exchange phase, and increased efficiency as a result of reuse the preexistence state value when it's renegotiated.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.856-858
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• 2013

The data which is sensed on USN(Ubiquitous Sensor Network) environment is concerned with personal privacy and the secret information of business, but it has more vulnerable characteristics, in contrast to common networks. In other words, USN has the vulnerabilities which is easily exposed to the attacks such as the eavesdropping of sensor information, the distribution of abnormal packets, the reuse of message, an forgery attack, and denial of service attacks. Therefore, the key is necessarily required for secure communication between sensor nodes. This paper proposes a KDPC(Key Distribution Protocol based on Cluster) using ECDH algorithm by considering the characteristics of sensor network. As a result, the KDPC can provide the safe USN environment by detecting the forgery data and preventing the exposure of sensing data.