• Journal of the Korea Institute of Information Security & Cryptology
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• v.12 no.1
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• pp.55-66
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• 2002

Electronic cash system based on anonymous coins have been invented by David Chaum. However, von Solms and Naccache discovered that such anonymous coins also very well suited to support criminals in Blacoailing. In this paper, we suggest a method that a client informs a bank of the information about blackmailing attack by using Schnorr identification protocol of XTR version at the stage of identification, whenever he is blackmailed. In general, blackmailing is the most serious among the various drawbacks of electronic cash system. Especially, blackmiling to be done when the client is kidnapped brings a fatal result to electronic cash system. But if the Schnorr identification protocol of XTR version is used, we can efficiently defeat blackmailing without assumption required in the existing method to defeat blackmailing.

• Journal of Korea Multimedia Society
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• v.8 no.7
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• pp.988-999
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• 2005

As the Internet continues to have the commercial trade changed, the method of payment is one of critical components to conduct successful businesses through the internet. An electronic cash has all of the characteristics of a traditional commodity cash and ensures the security for all transactions. Accordingly an internet billing system based on the electronic cash is expected as the secure and efficient payment method for the future electronic commerces. The digital contents such as digital merchandise and services have the characteristic that both the delivery of merchandise and the payment of money can be accomplished on the same network and are helpful to idealize the design of the electronic commerce system. In this paper, Anonymity got to be possible by using a virtual ID in the process of payment, the payment steps were decreased by being processed on the same network, and the efficiency and the security were guaranteed by decreasing the frequency of the coding and communication.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 1994.11a
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• pp.35-44
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• 1994

We propose an undeniable digital signature scheme which is practical since it has less computation and communication overhead than Chaum's one. We expect that this protocol be useful to develop secure systems such as electronic contract system, electronic mail system and electronic cash system.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.9 no.1
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• pp.103-114
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• 1999

Recently, various prototypes for electronic commerce are realized and its related researches are active under the present condition which it is increasing for the reality of its extended applications. First of all, actual demands are increasing for more secure and efficient electronic payment systems. Electronic cash, one of the Electronic payment systems, must have several properties like real money. Blind signature scheme by D. Chaum stands for the methods of obtaining privacy. In this paper, we propose a method for obtaining the blind signature based on the Elliptic Curve Cryptosystems, where the crytosystems are known as solving some problems of conventional crytosystems in views of computation time and key space. Also, we present a method for the divisibility of the electronic cash using our proposal by re-signing spare cash. Thus applying the proposed method, we can develop an efficient electronic payment systems.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2002.11a
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• pp.266-269
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• 2002

As a simulation or replacement of analog money in cyber space, the e-cash was introduced by using cryptographic primitives. Since a perfect anonymity system causes some illegal activities, such as money laundering, blackmailing, and illegal purchase, a revocable electronic system was paid a great attention to control the anonymity. In general, Trust Third Party(TTP) is introduced to detect any dubious user and coin, namely user tracing and coin tracing. In this paper we propose a new revocable anonymity e-cash system, and verify the security requirement as well. In our scheme a user first withdraws the e-coin from bank by using blind signature, and then TTP verifies the bank's signature and records the tracing information.

• The Journal of Information Technology
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• v.8 no.3
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• pp.159-176
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• 2005

The Purpose of this Article is to analyze the special settlement and electronic settlement system in the international trade. First, Factoring is a fast, easy and flexible way to improve a company's cash flow and generate working capital for the company. Factoring can be short-term or part of an ongoing financing program. New companies can benefit as well, since there is no requirement for a long-term credit history. Second, Forfaiting is a method of trade financing that allows exporters to obtain cash and be free of all risks by selling their medium term receivables on a 'without recourse' basis. Forfaiting can be an alternative to export credit or insurance cover, especially for those transactions in which the export credit agency is not open to a particular country and/or bank. Third, The Bolero System is jointly financed by SWIFT(Society for World International Financial Telecommunications) which handles most of the electronic funds transfer for banks, and the Through Transport Mutual Assurance Association(the TT Club), a mutual insurance association most of whose members are drawn from the Multimodal transport industry or transport intermediaries. Fourth, TradeCard is a payment and settlement system that is an alternative to letters of crdeit. That is, TradeCard is a business-to-business e-commerce infrastructure that enables buyers and sellers to conduct and settle international trade transactions securely over the Internet.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.6
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• pp.113-119
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• 2003

In WISA 2002, Ham et al. proposed a one-way mobile payment system. They claimed that the electronic cash of the system satisfies unforgeability and double spending prevention. In this paper, we point out that their system is not secure as they claimed by showing that the forgery of payment scripts is possible.

• Journal of the Korea Computer Industry Society
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• v.5 no.8
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• pp.801-810
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• 2004

It is only 2 ~ 3 years in the interior to be introduced as a Ubiquitous era after going through mainframe, PC and internet era on account of the advent of computer. This thesis intends to present a model device of an epoch-making cash management system using the RFID(Radio Frequency Identification) Tag and EPC (Electronic Product Code) Platform which are core technologies of the Ubiquitous Computing on the assumption that cable and wireless internet is constructed in university. Also this sets up a purpose to minimize the administrative procedure as well as the waste of time, people and cost which are problems of the cash management system operating now. Therefore as a research project hereafter, it will be able to present an imporvement device about the problems which cannot solve these days through the model of the proposing cash management system when the standardization, normalization and commercialization of advanced IT department are accomplished.

• The Journal of Information Technology
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• v.2 no.1
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• pp.35-52
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• 1999

This study introduced the new technologies that are expanding the realm of electronic commerce to the Internet and small business. Each of the key components of electronic commerce(contracts, signatures, notaries, payment systems and adult trails)are supported in the new electronic commerce. Electronic commerce is more than just handling purchase transactions and funds transfers over the internet. Despite Electronic commerce's past roots in transactions between large corporations, banks, and other financial institutions, the use of the internet as a way to bring Electronic commerce to the individual consumer has led to shift in viewpoint. Over the past few years, both the press and the business community have increased their focus on Electronic commerce involving the consumer Effective payment system should be established for the internet commerce. In this study, we examined the current development and application of Electronic payment system. Two different payment systems are used and under application. One is IC-card type of payment system which has gained popularity in England, Hong-Kong, and many other countries as a substitution of cash. The other type of payment system is e-cash, which is used more conveniently for the payment through internet. The question of which method is better fitted for the internet commerce should be evaluated in the view of cost and benefit since the associated technology is still under evolution. This study conducted a study on Secure Payment Method & Security Technology of Electronic Commerce

• Journal of Advanced Navigation Technology
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• v.11 no.1
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• pp.112-117
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• 2007

The Internet leads the transformation of the all-over social life with its radical diffusion and development. Moreover, it can be more focussed on the electronic commerce using the Internet - a new type of commerce, which is diffusion and developing. In the paper, we propose an electronic payment protocol with a network-type electronic-cash based on Public Key Infrastructure(PKI). The proposed protocol overcomes the problem of NetBill which deals with only contents and can't ensure anonymity. It also prevents illegal copy and distribution and insures the greatest safety by means of giving a certification number to the digital contents offered on the on-line.