• Journal of the Korea Society for Simulation
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• v.14 no.3
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• pp.137-146
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• 2005

In parametric approach to a signature verification, it generally uses so many redundant features unsuitable for each individual signature that it causes harm, instead. This paper proposes a method of determining personalized weights of a feature set in signature verification with parametric approach by identifying the characteristics of each feature. For an individual signature, we define a degree of how difficult it is for any other person to forge the one's (called 'DFD' as the Degree of Forgery Difficulty). According to the statistical characteristics and the intuitional characteristics of each feature, the standard features are classified into four types. Four types of DFD functions are defined and applied into the distance calculation as a personalized weight factor. Using this method, the error rate of signature verification is reduced and the variation of the performance is less sensitive to the changes of decision threshold.

• Journal of the Society of Naval Architects of Korea
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• v.53 no.6
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• pp.521-528
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• 2016

The surface of a naval ship emits infrared signature because it is mainly heated by the sun. In order to reduce infrared signature, it has been practiced to cool surface of the naval ship by using sea water. In this study, reduction effect of infrared signature was compared according to the parameters which affect emission of infrared signature in order to increase utility of sea water cooling. The analysis results by searching parameters, which can judge operation of sea water cooling, could be utilized as basic data for operation of the naval ship.

• Journal of the Korea Society of Computer and Information
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• v.5 no.3
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• pp.70-75
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• 2000

This paper first examines the problems of digital signatures concerning discrete logarithms and factorizations. Then the study introduces a blind signature that is based on digital signature. It also attempts to propose a new digital signature by excluding the use of inverse which has presumably caused problems in limited resources. Finally, the paper suggests a blind signature that can be offered by this new digital signature.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.2
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• pp.69-74
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• 2004

Threshold digital signature is very useful for networks that have no infrastructure such as ad hoc network Up to date, research on threshold digital signature is mainly focused on RSA and DSA. Though Schnorr's digital signature scheme is very efficient in terms of both computation and communication. its hard structure using interactive proof prevents conversion to threshold version. This paper proposes an efficient threshold signature. scheme based on the Schnorr's signature. It has a desirable property of scalability and reduces runtime costs by precomputation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.1
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• pp.287-304
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• 2022

With the development of quantum computers, ring signature schemes based on large integer prime factorization, discrete logarithm problem, and bilinear pairing are under threat. For this reason, we design a ring signature scheme based on lattice with a fixed verification key. Compared with the previous ring signature scheme based on lattice, our design has a fixed verification key and does not disclose the signer's identity. Meanwhile, we propose an anonymous electronic voting scheme by using our ring signature scheme based on lattice and (t, n) threshold scheme, which makes up for the lack of current anonymous electronic voting that cannot resist attacks of the quantum computer. Finally, under standard model (SM), we prove that our ring signature scheme based on lattice is anonymous against the full-key exposure, and existentially non-forgeable against insider corruption. Furthermore, we also briefly analyze the security of our anonymous electronic voting scheme.

• Journal of Information Processing Systems
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• v.12 no.2
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• pp.249-262
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• 2016

In 2004, Yang et al. proposed a threshold proxy signature scheme that efficiently reduced the computational complexity of previous schemes. In 2009, Hu and Zhang presented some security leakages of Yang's scheme and proposed an improvement to eliminate the security leakages that had been pointed out. In this paper, we will point out that both Yang and Hu's schemes still have some security weaknesses, which cannot resist warrant attacks where an adversary can forge valid proxy signatures by changing the warrant $m_w$. We also propose two secure improvements for these schemes.

• Journal of the Korean Mathematical Society
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• v.54 no.2
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• pp.545-561
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• 2017

The signature of a surface bundle over a surface is known to be divisible by 4. It is also known that the signature vanishes if the fiber genus ${\leq}2$ or the base genus ${\leq}1$. In this article, we construct new smooth 4-manifolds with signature 4 which are surface bundles over surfaces with small fiber and base genera. From these we derive improved upper bounds for the minimal genus of surfaces representing the second homology classes of a mapping class group.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10a
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• pp.607-609
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• 2003

본 연구는 기존의 인터넷 경매에서 Auctioneer와 Auction Issuer(AI)의 결탁을 막기 위한 안전하고 효율적인 경매 프로토콜인 blind signature protocol을 제안한다. 제안한 프로토콜에 사용되는 blind signature의 괴는 안전성과 속도면에서 우수한 ECC(Elliptic Curves Cryptosystem)에서 생성한다. 이는 이전의 blind signature키에 사용한 RSA 키사이즈의 정수위에서 구현하는 것 보다 훨씬 암호강도가 세며 속도가 빠르다. 따라서 제안한 프로토콜은 독단적인 Auctioneer의 행동을 막을 수 있으며, Auctioneer와 AI의 결탁이 없는 안전하고 효율적인 인터넷 경매를 할 수 있다.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.4 no.3
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• pp.271-276
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• 2004

This paper is a research on the dynamic signature verification of error rate which are false rejection rate and false acceptance rate, the size of signature verification engine, the size of the characteristic vectors of a signature, the ability to distinguish similar signatures, the processing speed and so on. Also, we present our efficient user interface and performance results.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 1997.11a
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• pp.111-119
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• 1997

본 논문에서는 Chaum이 처음으로 제안한 개념인 Blind signature를 타원곡선위에서 이산로그문제를 이용해 구현해보고 ECDSA와 Nyberg, Rueppel의 scheme을 Blind signature로 변형시킨 새로운 signature를 제시한다.