• Journal of Information Processing Systems
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• v.13 no.6
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• pp.1516-1526
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• 2017

Many organizations today use patch management systems to uniformly manage software vulnerabilities. However, the patch management system does not guarantee the integrity of the patch in the process of providing the patch to the client. In this paper, we propose a method to guarantee patch integrity through dual electronic signatures. The dual electronic signatures are performed by the primary distribution server with the first digital signature and the secondary distribution server with the second digital signature. The dual electronic signature ensures ensure that there is no forgery or falsification in the patch transmission process, so that the client can verify that the patch provided is a normal patch. The dual electronic signatures can enhance the security of the patch management system, providing a secure environment for clients.

• The KIPS Transactions:PartD
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• v.14D no.4 s.114
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• pp.373-380
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• 2007

Ubiquitous electronic commerce can offer anytime, anywhere access to network and exchange convenient informations between individual and group, or between group and group. To use secure ubiquitous electronic commerce, it is essential for users to have digital signature with the properties of integrity and authentication. The digital signature for ubiquitous networks is required neither a trusted group manager, nor a setup procedure, nor a revocation procedure etc. because ubiquitous networks can construct or deconstruct groups anytime, anwhere as occasion demands. Therefore, this paper proposes a threshold ring signature as digital signature for secure ubiquitous electronic commerce using the ring signature without forgery (integrity) and the (n,t) ring signature solving the problem cannot prove the fact which a message is signed by other signer. Thus the proposed threshold ring signature is ubiquitous group signature for the next generation.

• The KIPS Transactions:PartC
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• v.12C no.2 s.98
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• pp.169-174
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• 2005

Electronic signature system is required to be used in the promotion of the e-Commerce. Because the application system for electronic signature system has inconvenience and vulnerability of security, users are reluctant to use it. Therefore, the electronic signature system should give a guarantee of convenience and security. In this paper, we propose server-based application model, which uses identity information and makes users access transparently to solve electronic signature problems. We also design and verify electronic signature system that reduces threats to security, which cause server attack by distributing the part of signature key to both server and client. The application model with lightweight server system based on the electronic signature system is expected to be used in the promotion of the e-Commerce and help to make its business more efficient and competitive.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.11 no.3
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• pp.33-44
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• 2001

E-commerce has various advantages such as saving the cost and no constraint on time and space, unlike real-world commerce. On the other hand, e-commerce has some important issues to solve since the commerce is conducted on the cyberspace. The issues are a mutual confidence of parties participating in the commerce as well as a method of payments. On early days, electronic cash was designed using blind digital signature to protect the personal information from being exposed and to provide the perfect anonymity for user. In this paper, a new blind signature scheme based on Feige-Fiat-Shamir digital signature is proposed, which is very efficient compared with the other schemes in terms of the computational complexity. Also, a traceable Electronic Cash System which is based on the proposed blind digital signature is designed, which has a nice feature of identifying the spender in case of using the money illegally.

• Journal of Digital Contents Society
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• v.5 no.1
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• pp.1-6
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• 2004

Electronic cash is used as a payment tool for contents purchase in mobile electronic commerce environment. In order to protect customer`s privacy, we use blind signature. Blind signature has an anonymity property since it does not allow connection between customer`s ID and customer`s message. In this paper, we propose an blind signature scheme using elliptic curve algorithm based on Cap Diffie-Hellman Problem. Proposed scheme efficiently improved against existing blind signature scheme by reducing communication and computation time of the process.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.5
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• pp.945-957
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• 2012

Electronic documents have characteristics that detecting whether an electronic document is modified or not is not an easy process. Thus verifying integrity of documents is very important for using electronic documents. To facilitate this process, various electronic document software provide digital signature capabilities on themselves. However, there were not much research on the security of digital signature function of software. Therefore, in this paper, we analyze the security of Adobe PDF, MS Word, Hancom Hangul, digital notary service and digital year-end-settlement service, and propose recommendations for implementation of digital signature funcion.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.11
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• pp.5625-5641
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• 2017

Certificateless public key cryptography resolves the certificate management problem in traditional public key cryptography and the key escrow problem in identity-based cryptography. In recent years, some good results have been achieved in speeding up the computation of bilinear pairing. However, the computation cost of the pairing is much higher than that of the scalar multiplication over the elliptic curve group. Therefore, it is still significant to design cryptosystem without pairing operations. A multi-signer universal designated multi-verifier signature scheme allows a set of signers to cooperatively generate a public verifiable signature, the signature holder then can propose a new signature such that only the designated set of verifiers can verify it. Multi-signer universal designated multi-verifier signatures are suitable in many different practical applications such as electronic tenders, electronic voting and electronic auctions. In this paper, we propose a certificateless multi-signer universal designated multi-verifier signature scheme and prove the security in the random oracle model. Our scheme does not use pairing operation. To the best of our knowledge, our scheme is the first certificateless multi-signer universal designated multi-verifier signature scheme.

• International Commerce and Information Review
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• v.1 no.2
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• pp.229-247
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• 1999

Where a paper document, a manual signature, or negotiability is required in statute, then solutions must be found through a change in the law. However, where the problem originates in commercial usage, then the solution can be easier, and speedy. Certainly, nearly all of the functions that paper document provides can be equally, or better, satisfied by electronic means. That is, Electronic Commerce(EC), which has been increasing rapidly and is a new type of transaction, may be hindered by legal obstacles to use of Electronic Message, or by uncertainty to its legal effect and validity. Therefore, it is important to sustain legal effect to Electronic Message for the prosperity of EC The one of solutions is to use reliable Electronic signature system by Certification Authority to verify the authenticity of Electronic Message.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.14
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• pp.397-426
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• 2000

Since the internet is open to public in 1990, electronic commerce(EC) user has increase rapidly. Now EC is considered not only as communication method but also as new economical activities. EC is a kind of new commerce model which uses electronic means. And EC has global characteristics so that many country's legislation which regulates it differently makes an obstacle to vital of EC. The purpose of this study is to examine legal problems of internet electronic commerce. First, there are some legal problems whether electronic document has same legal function like traditional documents. Second, electronic signature must has authenticity, integrity, non-repudiation, writing and confidentiality in order to use looks like common signature. Finally, electronic contract is concluded on principle of mutual agreement. It is apparent that the concept of arrival is applied to the date and place in conclusion of electronic contract.

• The Transactions of the Korea Information Processing Society
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• v.6 no.11
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• pp.3046-3059
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• 1999

Kailar Accountability Logic proposed for the accountability analysis of communication protocols that require accountability and use asymmetric key digital signature is extended for protocols that use symmetric key digital signature. A proposed electronic micropayment protocol that uses symmetric key digital signature is analyzed to illustrate the use of the extend logic in detecting its lack f accountability and suggesting changes to enhance its accountability.