• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.4
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• pp.412-417
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• 2010

In this paper, we analyze the properties of nonlinear sequence generated by the shrinking generator. Also we propose a method for recovering the original sequence from intercepted bits by analyzing phase shifts of the output sequence using the properties of sequences generated from control register.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.1
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• pp.97-104
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• 2011

Pseudo-random sequences with high linear complexity and low correlation function values are widely used in communication and cryptology. In this paper, we study the properties of interleaved sequences generated by shrinking generator. And we give a method for obtaining the shrunken sequence from a partial description of the shrunken sequence by using the phase shifting of PN sequences generated by shrinking generator.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.9
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• pp.885-892
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• 2016

The nonlinear sequence generator called the shrinking generator was designed as nonlinear keystream generator composed by two maximum-length LFSRs. The shrunken sequences generated by the shrinking generator are included in the class of interleaved sequences and can be modelled as one of the output sequences of cellular automata (CA). In this paper, we propose a method for synthesizing a 90/150 CA-based sequence generator to generate a family of sequences with the same characteristic polynomial as the shrunken sequences.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.10
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• pp.2283-2291
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• 2010

The shrinking generator which is one of clock-controlled generator is a very simple generator with good cryptographic properties. A nonlinear sequence generator based on two 90/150 maximum length cellular automata can generate pseudorandom sequences at each cell of cellular automata whose characteristic polynomials are same. The nonlinear sequence generated by cellular automata has a larger period and a higher linear complexity than shrunken sequence generated by LFSRs. In this paper we analyze shrunken-interleaved sequence based on 90/150 maximum length cellular automata. We show that the sequence generated by nonlinear sequence generator based on cellular automata belongs to the class of interleaved sequence. And we give an effective algorithm for reconstructing unknown bits of output sequence based on intercepted keystream bits.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.11
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• pp.2507-2513
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• 2010

In this paper, we show that the shrinking generator with two LFSR whose characteristic polynomials are primitive is an interleaving generator and analyze phase shifts in shrunken sequence. Also for a given intercepted sequence of shrunken sequence, we propose. the method of reconstructing some deterministic bits of the shrunken sequence using phase shifts.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.1
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• pp.179-184
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• 2020

Cellular automata (CA), which is known as a pseudo random number generator due to its excellent randomness, has various applications. Cho et al. designed a CA-based shrinking generator to generate a long period of nonlinear sequence. In addition, chaotic cat maps have been studied by many researchers as the complex nonlinear dynamics systems with sensitivity in initial conditions and unpredictable characteristics. In this paper, we propose a new image encryption method using nonlinear sequence generated by CA-based shrinking generator with maximum period and 3D chaotic cat map for high security.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2002.11a
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• pp.88-91
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• 2002

자기 수축 발생기(self-shrinking generator)는 Meier와 Staffelbach에 의해 제안되었으며[4], 구조가 간단하고 키수열을 생성하는 속도가 빠르기 때문에 스트림 암호시스템으로 각광받고 있다 [5]. 본 논문에서는 자기 수축 발생기의 새로운 구성방법을 제안한다. 제안된 자기 수축 발생기는 하나의 선형귀환회로와 주어진 짝수 m에 의하여 정의되며 일반적으로 선형귀환회로의 귀환다항식으로 원시다항식을 사용한다. 이 경우 키수열은 균형성을 만족하며, 선형귀환회로의 귀환다항식의 차수를 $d_{Y}$ 라고 하면 주기는 $d_{Y-2}$ 이다. m을 $2^{η}$ζ로 표현하면 선형복잡도 Lz는 $d_{Y}$ ＋η-3/$\leq$ $L_{Z}$ $\leq$m/2($d_{Y}$ -1 - ($d_{Y}$ -2))이다. 따라서 제안된 자기 수축 발생기는 기존의 자기 수축 발생기에 비하여 암호학적으로 우수한 성질을 갖는다.다.

• Korea Journal of Geothermal Energy
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• v.5 no.3
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• pp.4-11
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• 2009

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.5
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• pp.1104-1109
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• 2015

Due to the rapid growth in digital contents, it is important for us to design a high speed and secure encryption algorithm which is able to comply with the existing and future needs. This paper proposes an alternative approach for self-decimated LM-128 summation sequence generator, which will generate a higher throughput if compared to the conventional generator. We design and implement a threshold clock-controlled LM-128 and prove that it has a lower clock cycle and hence giving a higher key stream generation speed. The proposed threshold clock-control LM-128 generator consists of 256 bits inner state with 128 bits secret key and initialization vector. The cipher achieves a security level of 128 bits to be adapted to the digital contents security with high definition and high quality.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.208-208
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• 2013

ZnO는 직접천이형 반도체로 약 3.37 eV의 넓은 에너지 band-gap과 60 meV의 비교적 큰 엑시톤 결합 에너지를 가지고 있다. 또한 단결정 성장 가능과 투명성 등 많은 장점들로 인하여 GaN와 대체할 자외선 또는 청색 발광소자나 ITO를 대체할 투명전극 같은 광범위한 광전소자로 큰 주목을 받으며 연구되어 왔다. 이러한 ZnO는 다양한 물질들의 첨가를 통해 인위적으로 특성변화가 가능한데 Mg, Be, Cd 첨가를 통한 에너지 밴드갭의 확장과 수축, Al 첨가를 통한 전기전도성의 증가 등이 그 예이다. 최근에는 밴드갭 조절을 이용한 ZnO-ZnMgO와 같은 이종접합구조가 광소자 등의 응용을 목적으로 많은 연구가 이루어지고 있다. 더불어 나노선이나 나노막대 같은 1차원 구조를 갖는 ZnO 계열 반도체의 연구는 현재 큰 이슈가 되고 있는 나노 크기의 소자 개발에 매우 큰 적용 가능성을 가지고 있다. 우리는 수열합성법을 이용하여 hexagonal ZnO 나노막대를 성장하고 그 표면에 core-shell 형태의 $ZnO-Zn_{1-x}Mg_xO$ (x=0.084) 양자우물을 원자층증착법으로 증착하였다. 본 연구에서는 만들어진 ZnO 나노막대와 ZnO-ZnMgO 나노막대, core-shell ZnO-ZnMgO 양자우물 sample들의 저온(5 K) Photoluminescence 측정을 통하여 광학적 band 구조를 분석하였다. 실험적으로 의도된 양자우물 두께와 다른 실제 형성된 양자무물의 두께를 알아내기 위하여 2차원 hexagonal 양자우물 band 구조에서 self-consistent nonlinear Poisson-Schr$\"{o}$dinger 방정식 계산과 컴퓨터 시뮬레이션을 이용하였으며, 이 방법으로 계산된 값과 실험값의 비교를 통하여 실제 형성된 양자우물의 두께를 정량적으로 유출할 수 있었다.