• Proceedings of the Korean Information Science Society Conference
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• 2003.10a
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• pp.724-726
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• 2003

‘키로밍(Key Roaming)’서비스는 임의의 단말기에서 인증서, 전자서명 둥의 사용자의 비밀정보를 네트워크를 통해서 접근할 수 있는 기능을 지원한다. 현재 은행의 뱅킹 시스템이나 그 밖의 인터넷 서비스에서는 비밀정보를 사용자의 컴퓨터에 저장해서 사용한다. 그러나 사용자가 그 비밀정보를 다른 컴퓨터에서 사용하고자 할 때에는 디스크나 스마트카드와 같은 보조기억장치에 저장해야 하는 불편함이 존재한다. 종래의 이러한 방식은 사용이 불편할 뿐만 아니라 공간과 비용치 부담이 크므로 키로밍 프로토콜에 대한 요구가 더욱 증대하였다. 키로밍 프로토콜은 공간과 비용의 절감이라는 효과가 있지만 해결해야 할 보안상의 문제가 존재하며 이 문제점들을 해결하기 위한 많은 방법들이 제시되어 왔다. 본 논문에서는 베리사인의 프로토콜과 한국정보 보호센타에서 제시한 다중서버를 이용하는 프로토콜에 대해서 살펴본 후 그 문제점을 지적하고 이를 해결 할 수 있는 새로운 프로토콜을 제안한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.11a
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• pp.534-536
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• 2014

CCTV의 다양한 필요성이 대두됨에 따라 CCTV를 통합관리하는 CCTV 통합관제 센터가 늘어나고 있다. 행정안전부는 2015년까지 전국 시군구에 CCTV 통합관제센터 구축을 추진하고 있을 정도로 앞으로도 계속적으로 증가할 예정이다. 하지만 이를 관리할 전문 모니터링 요원이 턱없이 부족한 상황이며, 전문 교육의 부재로 CCTV 영상을 개인적 호기심이나 개인의 이익을 위해 열람하는 경우가 발생하고 있다. 본 논문을 비밀 분산 기법을 이용하여 암호화된 키를 분배하고 요청에 따라 일정 수 이상의 분배키가 모이면 영상 열람권한을 주는 방식으로 설계 하여 관리자가 임의로 영상정보에 접근하는 상황을 방지하였다. 또한 그룹 키를 분배하고 수시로 키 갱신을 함으로서 다양한 보안 위협에 대응 하였다.

• Journal of the Korea Computer Industry Society
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• v.3 no.8
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• pp.1105-1116
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• 2002

This paper has presented three types of key recovery methods, which are known as key escrow, key encapsulation, and trusted third party scheme. we have analyzed the existing key recovery products, which have been developed by the advanced nations for electronic commerce and electronic government. we have also analyzed the key recovery policies proposed by the advanced nations, such as The United States of America, Great Britain, and Japan. In this paper, several key recovery policies are proposed for the e-commerce and e-government system. And we have proposed key recovery scheme for the e-commerce system utilizing the on-line secret sharing scheme based on the Internet and public bulletin board.

• Journal of Internet Computing and Services
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• v.14 no.3
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• pp.15-21
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• 2013

Due to the widespread propagation of mobile platforms such as smartphones and tablets, financial and e-commercial transactions based on these mobile platforms are growing rapidly. Unlike PCs, almost all mobile platforms do not provide physical keyboards or mice but provide virtual keypads using touchscreens. For this reason, an attacker attempts to obtain the coordinates of touches on the virtual keypad in order to get actual key values. To tackle this vulnerability, financial applications for mobile platforms use secure keypads, which change position of each key displayed on the virtual keypad. However, these secure keypads cannot protect users' private information more securely than the virtual keypads because each key has only 2 or 3 positions and moreover its probability distribution is not uniform. In this paper, we analyze secure keypads used by the most financial mobile applications, point out the limitation of the previous research, and then propose a more general and accurate attack method on the secure keypads.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.3
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• pp.77-89
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• 2005

As the ID-based public key cryptosystems become a very active research area, a number of ID-based key agreement protocols have been proposed, but unfortunately many of them were analyzed that there were some security flaws in the protocols. In addition to key agreement protocols, in recent, Liu et al. and Kim et al. proposed the key agreement protocols that multiple session keys are established at once among participated entities. In this paper, we propose an ID-based tripartite key agreement protocol that establishes 8 keys by improving the efficiency of the Liu et al's. Moreover, the proposed protocol can be used in the situation where multiple different private key generators(PKG) are involved. Therefore, because the private key issued by different PKGs belonging to each entity's domain can be used, our proposed scheme is more efficiently applicable to the practical applications.

• Journal of KIISE:Information Networking
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• v.35 no.6
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• pp.465-473
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• 2008

The MQV protocol has been regarded as the most efficient authenticated Diffie- Hellman key exchange protocol, and standardized by many organizations including the US NSA. In Crypto 2005, Hugo Krawczyk showed vulnerabilities of MQV to several attacks and suggested a hashed variant of MQV, called HMQV, which provides the same superb performance of MQV and provable security in the random oracle model. In this paper we suggest an efficient authenticated Diffie-Hellman key exchange protocol providing the same functionalities and security of HMQV without random oracles. So far there are no authenticated Diffie-Hellman protocols which are provably secure without using random oracles and achieve the same level of security goals of HMQV efficiently yet.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06d
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• pp.95-100
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• 2010

높은 이동성 및 휴대성을 갖는 모바일 디바이스의 기술적 발전은 사용자로 하여금 보다 높은 수준의 통합된 편의 기능 제공이 요구되고 있다. 이러한 예로 기존 물리적 지갑에 보관하던 플라스틱 신용카드, 멤버쉽 카드, 신분증 등의 개인정보를 모바일 디바이스 안에 저장 관리하는 모바일 지갑 서비스가 현실화되고 있다. 모바일 지갑을 통한 상거래 서비스를 이용할 시 디바이스에 저장된 각종 개인정보가 근거리 무선통신 기술을 통해 다른 모바일 기기나 지불서버에 전달되는 데, 이 무선전송 구간은 근원적으로 많은 보안 취약점을 갖고 있다. 따라서 본 논문에서는 모바일 지갑 응용 서비스에 모바일 기기간 안전한 키 설정 시 공개키 인증서를 활용하지 않고 두 기기간 공유키 검증을 할 수 있는 세션 키 검증 기술들을 분석하고, 해당기술들을 구현하여 모바일 지갑 결제 테스트베드에 포팅한 실험 결과를 통한 성능분석 결과를 제시한다. 본 성능평가를 통해 향후 다양한 모바일 기기 특성에 따른 최적의 세션 키 공유 키 검증 방법 선택 시 유용한 근거자료로 활용할 수 있을 것으로 기대된다.

• Journal of the Korea Society of Computer and Information
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• v.12 no.3
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• pp.19-26
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• 2007

In recent rears. web portal system has received much attention as a user interface for the grid environment. Grid system uses symmetric key for authenticating user identity while the traditional portal system does a password-based authentication. Regarding this, many researches are progressing to integrate portal accounts with symmetric key. Specially. researches such as GAMA and PURSE are active and those focus on easy usability for users who familiar with password-based authentication. However the protection of data and resources is a critical issue in Grid environment, because those are shared through a wide-area network. In this paper, we suggest a new authentication mechanism which unify authentication mechanisms between portal system and grid service by using symmetric key. It will improve a security level in UI layer as much as in grid service.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.1 no.1
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• pp.47-65
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• 1991

An ID-based scheme provides a very efficient solution to the key distribution problem, since it can solve bothe the authentication problem and the communication complexity problem in a public key scheme. Especilly, and ID-Based ndninterative key distribution system plays an crucial roie in the one-way communication environment such as secure electronic mail, owing to its noninteractiveness. This paper aims at analyzing the previously proposed scheme s and providing possible improvements. It also demonstraes that the Maurey-Yacobi's scheme presented in Eurocry'91 is not secure, and provikdes an countemeasure to overcome the security problem.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.5
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• pp.915-932
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• 2022

According to the Personal Information Protection Act and Pseudonymization Guidelines, the mapping is processed to the hash value of the combination key generation items including Salt value when different combination applicants wish to combine. Example of combination key generation items may include personal information like name, phone number, date of birth, address, and so on. Also, due to the properties of the hash functions, when different applicants store their items in exactly the same form, the combination can proceed without any problems. However, this method is vulnerable to combination in scenarios such as address changing and renaming, which occur due to different database update times of combination applicants. Therefore, we propose a privacy preserving combination key generation scheme robust to updates of items used to generate combination key even in scenarios such as address changing and renaming, based on the thresholds through probabilistic record linkage, and it can contribute to the development of domestic Big Data and Artificial Intelligence business.