• Convergence Security Journal
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• v.5 no.3
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• pp.23-32
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• 2005

This paper presents a 128-bit Reversible Cellular Automata (RCA) based lightweight block cipher for Ubiquitous computing security. To satisfy resource-constraints for Ubiquitous computing, it is designed as block architecture based on Cellular Automata with high pseudo-randomness. Our implementation requires 704 clock cycles and consumes 2,874 gates for encryption of a 128-bit data block. In conclusion, the processing time outperformed that of AES and NTRU by 31%, and the number of gate was saved by 20%. We evaluate robustness of our implementation against both Differential Cryptanalysis and Strict Avalanche Criterion.

• Journal of IKEEE
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• v.23 no.1
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• pp.200-206
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• 2019

Recently, there is a growing preference for a fast and secure cryptographic protocol that is applicable to Internet of things environments. Among the lattice-based cryptographic algorithms, the NTRU cryptosystem is secure by virtue of the shortest vector problem (SVP) and the closest problem(CVP), which is a problem of finding very short vectors and closest vector. NTRUSign, an electronic signature based on this cryptographic algorithm, has been proposed and proved unsafe for script attacks. In this paper, we propose a security protocol using a symmetric key algorithm by securing a shared key using key exchange. Therefore, the attacker can not compute the key value and intends to propose a more secure digital signature.

• 한국IT서비스학회:학술대회논문집
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• 2009.05a
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• pp.205-208
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• 2009

이 논문에서는 RFID(Radio Frequency IDentification)에 대한 여러 가지 보안위협에 대하여 간단히 알아보고 그에 대응하는 안전한 암호학적 도구(Primitive)에 대하여 알아보겠다. 공개키 암호시스템(PKC, Public Key Cryptosystem)에 사용되는 타원곡선(EC, Elliptic Curve) 암호, NTRU(N-th degree TRUncated polynomial ring) 암호, Rabin 암호 등은 초경량 하드웨어 구현에 적합한 차세대 암호시스템으로서 안전한 RFID 인증서비스 제공과 프라이버시보호를 가능케 한다. 특히, 본고에서는 초경량 키의 길이, 저전력 소모성, 고속구현 속도를 갖는 타원곡선암호의 안전성에 대한 가이드라인을 제공하겠다.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2003.12a
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• pp.399-405
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• 2003

A new type of signature scheme, called NTRUSign, based on solving the approximately closest vector problem in an NTRU lattice was proposed in［7］,［8］. However no security proof against chosen messages attack has been made for this scheme. In this paper, we show that NTRUSign signature scheme contains the weakness of malleability. From this, one can derive new valid signatures from any previous message-signature pair which means that NTRUSign is not secure against strongly existential forgery.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.3
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• pp.439-448
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• 2017

It is news from nowhere that post-quantum cryptography has side-channel analysis vulnerability. Side-channel analysis attack method and countermeasures for code-based McEliece cryptosystem and lattice-based NTRU cryptosystem have been investigated. Unfortunately, the investigation of the ring-LWE cryptosystem in terms of side-channel analysis is as yet insufficient. In this paper, we propose a chosen ciphertext simple power analysis attack that can be applied when ring-LWE cryptography operates on 8-bit devices. Our proposed attack can recover the key only with [$log_2q$] traces. q is a parameter related to the security level. It is used 7681 and 12289 to match the common 128 and 256-bit security levels, respectively. We identify the vulnerability through experiment that can reveal the secret key in modular add while the ring-LWE decryption performed on real 8-bit devices. We also discuss the attack that uses a similarity measurement method for two vectors to reduce attack time.

• Journal of Korea Multimedia Society
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• v.21 no.4
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• pp.485-492
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• 2018

Recently, the numerous authentication and key distribution protocol for NFC payment environment have been proposed using public key cryptosystems. However, these protocol are vulnerable to quantum computing attack because quantum computing can solve factoring and discrete logarithm problem effectively using Grover and Shor's algorithm. For these reason, the secure authentication and key distribution have become a very important security issue in order to prevent quantum computing attacks. Therefore, to ensure user's payment information and privacy, we propose a secure quantum resistant authentication and key distribution protocol for NFC payment environments.

• Review of KIISC
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• v.32 no.1
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• pp.47-56
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• 2022

NIST는 PQC Round 3 평가 기준으로 부채널 분석 및 오류 주입에 대한 안전성을 역설함에 따라 Round 3 양자내성암호에 대한 새로운 부채널 공격 시나리오 및 대응 기법이 빠르게 제시되고 있다. 따라서 각 방법론의 동향을 파악하고 재정의, 분류하는 작업이 필수적으로 요구된다. 본 논문에서는 NIST PQC Round 3 최종 후보 중 격자 기반 암호 KEM(SABER, CRYSTALS-KYBER, NTRU)에 대한 부채널 분석기법 및 대응기술 동향을 조사 및 분석하고 향후 Round 3 격자 기반 KEM 알고리즘의 부채널 연구 전망을 논의한다.

• Review of KIISC
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• v.33 no.3
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• pp.39-47
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• 2023

양자컴퓨팅 기술이 발전함에 따라, 양자컴퓨터를 이용한 공격에도 안전한 암호인 양자내성암호(Post-Quantum Cryptography, PQC) 기술의 중요성이 대두되고 있다. NIST에서는 2016년부터 시작된 표준화 공모 1,2,3 라운드를 통해 2022년 공개키 암호 및 Key-establishment, 전자서명 분야의 양자내성암호 표준을 선정한 바 있으며, 현재는 4 라운드와 전자서명 분야 추가 선정 공모를 진행 중이다. 이러한 배경에서 2022년 국내에서도 양자내성암호 알고리즘 표준화 공모인 KpqC 공모전 1라운드를 시작하였고, 공개키 암호 및 Key-establishment 7종, 전자서명 9종의 알고리즘이 표준 후보로 제출되었다. 본고에서는 KpqC 공모전 1 라운드 공개키 암호 및 Key-establishment 알고리즘 중 격자 기반 공개키 암호/KEM(Key Encapsulation Mechanism) 알고리즘 3종 NTRU+, SMAUG, TiGER에 대해 분석 및 소개한다. 각 알고리즘의 기반 문제, 설계 방식, 특징, 안전성 분석 방식 등을 분석하고, 구현성능을 비교 분석한다.