• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.824-827
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• 2003

With a rapid development of Information Telecommunication technique, network communication environment has been greatly improved. People come to feel more convinient to purchase products through Internet. Accordingly, various kinds of electronic payment systems have been developed and used. In this paper, we propose an algorithm which not only can associate the broker system with an electronic cash user, but also regenerate all amount of money previously paid using technique such as Meta-Message recovery and a RSA Blind Signature based on discrete logarithm problem.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.9 no.1
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• pp.85-102
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• 1999

In this paper, we propose an EC-SRP(Elliptic Curve - Secure Remote Password) protocol that uses ECDLP(Elliptic Curve Discrete Logarithm Problem) instead SRP protocols’s DLP. Since EC-SRP uses ECDLP, it inherits the high performance and security those are the properties of elliptic curve. And we reduced the number of elliptic curve scalar multiplication to improve EC-SRP protocol’s performance. Also we have proved BC-SRP protocol is a secure AKC(Authenticated Key Agreement with Key Confirmation) protocol in a random oracle model.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.9 no.2
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• pp.73-82
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• 1999

In an open network computing environment a host cannot to identity its users correctly to network services. In order to prevent this thing we present the design of a authentication scheme 솟 using the notion of rth -residuosity problem and discrete logarithm problem which is proposed by S. J. Park et al. The proposed scheme described here is efficient method for mutual authentication without leakage of users identity in mobile communication system that ensure user anonymity and untraceability.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.9 no.4
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• pp.61-70
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• 1999

In this paper we propose the verifiable self-certified schemes(key distribution scheme identification scheme digital signature scheme) based on ${\gamma}$th -residuosity which make up for defects of Girault's self-certified schemes allow the authenticity of public keys to be verified during the use of the keys. The security of our schemes is based on the difficulty of ${\gamma}$th -residuosity problem and discrete logarithm problem simultaneously.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.581-583
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• 2017

Elliptic curve cyptography is relatively a current cryptography based on point arithmetic on elliptic curves and the Elliptic Curve Discrete Logarithm Problem (ECDLP). This discrete logarithm problems enables perfect forward secrecy which helps to easily generate key and almost impossible to revert the generation which is a great feature for privacy and protection. In this paper, we provide a lightweight Elliptic Curve Diffie-Hellman (ECDH) Key exchange generator that creates a 163 bit long shared key that can be used in an Elliptic Curve Integrated Encryption Scheme (ECIES) as well as for key agreement. The algorithm uses a fast multiplication algorithm that is small in size and also implements the extended euclidean algorithm. This proposed architecture was designed using verilog HDL, synthesized with the vivado ISE 2016.3 and was implemented on the virtex-7 FPGA board.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.1 no.1
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• pp.3-15
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• 1991

in 1984 Shamir proposed the concept of ID(identity)-based cryptosystem and digital signature scheme wich does not require any public file for storing the user' s public keys. In this paper, the concept of the ID-based cryptosystem based on discrete logarithm problem using the conven-tional public-key cryptosystems is described, and the implementation method of the ID-based cryptosystem is also presented. The new digital signaturw schme based on the ID-based crypto-system is proposed and possible atacks are considered and analyzed for the security of digital signature scheme. The proposed ID-based schemes are particularrly useful for smart card and personal identification card application.

• 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.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.1 no.1
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• pp.91-96
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• 1991

The key exchange idea by using a reduced binary indefinite quadratic form has been introdu-ced. This is based on the difficulty of solving the discrete logarithm problem on the class group of a real quadratic field.

• Journal of Electrical Engineering and information Science
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• v.1 no.2
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• pp.87-95
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• 1996

This paper presents a (k,n) threshold digital signature scheme with no trusted dealer. Our idea is to use the EIGamal signature scheme modified for group use. Among many digital signature schemes, our modification has a nice property for our purpose. We also show a (k.n) threshold fail stop signature scheme and two (k.n) threshold undeniable signature schemes. We use [10] as the original fail stop signature scheme, and use [3] and [2] as the original undeniable signature schemes. Since all these schemes are based on the discrete log problem, we can use the same technique.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.1
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• pp.90-96
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• 2011

In this paper, we propose a new discrete logarithm problem(DLP) based on the class semigroups of imaginary quadratic non-maximal orders using the special character of non-invertible ideal and analysis its security. To do this, we first explain the mathematical background explicitly and prove some properties of Cls (O) which relate to constructing the DLP and guaranteeing the security. To test the security of the proposed DLP, we compare the class number of the maximal order with that of the non-maximal order and investigate the unique factorization problems of ideals between class groups of the maximal orders and class semigroups of non-maximal orders to ensure the security of the cryptosystem.