• Proceedings of the Korea Information Processing Society Conference
• /
• 2002.04b
• /
• pp.975-978
• /
• 2002

인터넷의 급속한 보급과 초고속정보통신망의 구축으로 인해 여러 분야에서 전자투표가 실현될 수 있으며, 그에 따라서 선거 비용이 절감되고 투표 장소의 제약이 개선될 것으로 예상된다. 그러나 전자투표의 실용화를 위해서는 공정성과 안전성 등의 문제가 해결되어야하며, 이를 위해 각종 암호 기반을 사용하여 프로토콜을 구성한다. 이 논문에서는 투표 과정에서 투표자를 그룹화하며, 은닉 서명 기법을 이용하는 전자투표 방법을 제안한다. 이 방법은 복잡한 익명 통신로를 사용하지 않으면서도 투표자의 익명성을 보장한다. 또한 투표자가 자신의 투표 결과를 제3자에게 증명할 수 없으므로 최근에 심각한 문제로 대두되고 있는 투표의 매매를 방지할 수 있다.

• The KIPS Transactions:PartD
• /
• v.12D no.3 s.99
• /
• pp.499-506
• /
• 2005

A hash chain is a structure organized by hash function with high speed in computation. Systems using the hash chain are using extensively in various cryptography applications such as one-time passwords, server-supported signatures and micropayments. However, the most hash chain based on the system using pre-paid method provides anonymity but has the problem to increase payment cost. In this paper, we propose a new hash chain based on the micropayment system to keep user anonymity safe through blind signature in the withdrawal process of the root value without disclosing privacy information, and to improve efficiency by using secret key instead of public key in the system without the role of certificate.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.9 no.4
• /
• pp.23-36
• /
• 1999

As the blind signature(10) does not reveal any information about the message or its signature it has been used for preventing the information leakage and for providing the anonymity in secure electronic payment systems. Unfortunately this perfect anonymity could be misused by criminals as blind signatures prevent linking the withdrawal of money nd the payment made 표 the same customer. Therefore we should provide publicly verifiable mechanism if it is required for the judge to trace the blackmailed messages. In this paper we propose a modified blind signature scheme which additionally provides the role of message recovery after analyzing the existing meta-ELGamal scheme(12) suggested by Horster. And we suggest a new fair blind multi-signature scheme based on the oblivious transfer protocol with which a judge can publicly verify its fairness and correctness if needed. Proposed scheme can also applicable to the diverse electronic payment applications.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2002.11c
• /
• pp.2207-2210
• /
• 2002

무선 전자상거래(M-Commerce) 전자지불 방식의 하나인 전자화폐는 실물 화폐와 유사한 성질을 만족해야 한다. 본 논문에서는 지불된 전자화폐가 악용되었을 때 신뢰센터가 필요로 하는 경우 전자화폐 사용자와 브로커를 연관지을 수 있고 이산대수문제에 기반 한 메타-메시지 복원과 은닉 RSA서명 기법을 이용하여 이미 지불된 금액을 재생성 할 수 있는 알고리즘을 제안한다.

• The KIPS Transactions:PartC
• /
• v.8C no.6
• /
• pp.757-764
• /
• 2001

The increase of electronic commerce leads to the increasing attention to the way customers pay and a large number of researches on payment system. Recently many researches on a system which provides anonymity in order to protect user\`s privacy have been carried out. And some potential problems from that system are being reviewed by anonymity control system. This thesis will include the following. First, I want to analyze the old scheme related to divisible and examine general ideas of anonymity control. Second, I propose a new blind signature in addition to KCDSA, the standard digital signature in Korea. The last one I want to propose is a new electronic cash system with the divisible for more efficient use of electronic cash which can control anonymity with the help of trustee.

• The Journal of the Korea Contents Association
• /
• v.1 no.1
• /
• pp.83-92
• /
• 2001

In this study, we combine information hiding technique with digital contents protection scheme. For providing secure distribution on digital contents, a new paradigm can be proposed after considering both watermarking and fingerprinting techniques. In detail, publicly verifiable digital signature schemes are applied into digital contents. On signing digital copyrights, we can publicly verify its correctness if needed.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.3C
• /
• pp.293-298
• /
• 2008

Recently, with the development of mobile techniques and the consideration to conveniency of using, the research on Mobile RFID Reader technique is getting more and more attentions. Until now, all security authentication algorithms of RFID are algorithms about range between Tag and Reader. The range between Reader and backend DB is composed by wired networks, so it's supposed to be secure range. But it must be taken account of the problem of information security and privacy in wireless range during the design of Mobile RFID Reader. In this paper we design an blind signature scheme based on weil-paring finite group's ECC encryption scheme, and by using this blind signature we propose the anonymous authorization scheme to Mobile RFID Reader's users.

• Journal of the Korea Convergence Society
• /
• v.9 no.11
• /
• pp.75-81
• /
• 2018

Anonymity and privacy issues are becoming important as all transactions in the blockchain are open to users. Public blockchains appear to guarantee anonymity by using public-key addresses on behalf of users, but they can weaken anonymity by tracking with various analytic techniques based on transaction graph. In this paper, we propose a scheme to protect anonymity and privacy by converging various security techniques such as k-anonymity, mixing, blind signature, multi-phase processing, random selection, and zero-knowledge proof techniques with incentive mechanism and contributor participation. Through performance analysis, our proposed scheme shows that it is difficult to invade privacy and anonymity through collusion attacks if the number of contributors is larger than that of conspirators.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.15 no.1
• /
• pp.12-17
• /
• 2005

The segment matching method shows better performance than the global and points-based methods to compare reference signature with an input signature. However, the segment-to-segment matching method has the problem of decreasing recognition rate according to the variation of partitioning points. This paper proposes a fusion model based on the segment matching and HMM to construct a more reliable authentic system. First, a segment matching classifier is designed by conventional technique to calculate matching values lot dynamic information of signatures. And also, a novel HMM classifier is constructed by using the principal component analysis to calculate matching values for static information of signatures. Finally, SVM classifier is adopted to effectively combine two independent classifiers. From the various experiments, we find that the proposed method shows better performance than the conventional segment matching method.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
• /
• 1997.11a
• /
• pp.378-383
• /
• 1997

D. Chaum은 RSA암호알고리듬을 이용한 은닉서명방법으로 전자현금시스템을 제안했다. 그러나 이 방법은 사용자가 은행으로부터 전자현금을 발행받을 때 cut-and-choose방법을 사용함으로써 큰 통신부하(communication overhead)를 가지는 비효율적인 면이 있다. 본 논문은 제비뽑기방법을 이용하여 cut-and-choose방법을 사용하지 않고 사용자의 프라이버시를 보호하는 새로운 전자현금시스템을 제안한다.