• ETRI Journal
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• 제45권6호
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• pp.1090-1102
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• 2023

Authenticated multiple key agreement (AMKA) protocols provide participants with multiple session keys after one round of authentication. Many schemes use Diffie-Hellman or authenticated key agreement schemes that rely on hard integer factorizations that are vulnerable to quantum algorithms. Lattice cryptography provides quantum resistance to authenticated key agreement protocols, but the certificate always incurs excessive public key infrastructure management overhead. Thus, a lightweight lattice-based secure system is needed that removes this overhead. To answer this need, we provide a two-party lattice- and identity-based AMKA scheme based on bilateral short integer or computational bilateral inhomogeneous small integer solutions, and we provide a security proof based on the random oracle model. Compared with existing AMKA protocols, our new protocol has higher efficiency and stronger security.

• 한국IT서비스학회지
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• 제3권2호
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• pp.119-127
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• 2004

A mobile ad hoc network(MANET) is a network where a set of mobile devices communicate among themselves using wireless transmission without the support of a fixed network infrastructure. The use of wireless links makes MANET susceptible to attack. Eavesdroppers can access secret information, violating network confidentiality, and compromised nodes can launch attack from within a network. Therefore, the security for MANET depends on using the cryptographic key, which can make the network reliable. In addition, because MANET has a lot of mobile devices, the authentication scheme utilizing only the symmetric key cryptography can not support a wide range of device authentication. Thereby, PKI based device authentication technique in the Ad Hoc network is essential and the paper will utilize the concept of PKI. Especially, this paper is focused on the key management technique of PKI technologies that can offer the advantage of the key distribution, authentication, and non-reputation, and the issuing and managing technique of certificates based on clustering using Threshold Cryptography for secure communication in MANET.

• 한국정보통신학회논문지
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• 제21권7호
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• pp.1411-1419
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• 2017

PKI(Public Key Infrastructure) 인증은 개인키 소지(possession)와 개인키 보호 패스워드 지식(knowledge)이라는 2 요소 인증(2 factor authentication) 능력과 안전한 공개키 암호 프로토콜을 통해 인터넷 거래의 신뢰 인프라 구축에 많은 기여를 해왔다. 하나의 인증서로 모든 PKI 사이트를 접근할 수 있는 점도 PKI 인증의 활성화에 기여하였다. 그럼에도 불구하고 인증서 인프라 구축 비용, 인증서 관리에 따른 사용자 불편함, 그리고 개인키 보호 패스워드 관리의 어려움 등에 따른 여러 가지 문제점들이 노출되어 왔다. 최근에 주목받고 있는 FIDO(Fast IDentity Online) 인증은 PKI 인증과 같이 공개키 암호 프로토콜에 기초한 강력한 인증 서비스를 제공하면서도 사용자별 인증서 발급이 불필요하고, 생체 인증 등과 결합하여 안전하고 편리한 인증 서비스 제공을 추구하고 있다. 본 논문은 PKI 인증과 FIDO 인증의 동작 방식을 구체적으로 비교하여 각각의 장단점을 분석하고, 그에 따른 각각의 응용 분야를 제시하는 데 목적이 있다.

• Journal of Communications and Networks
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• 제11권6호
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• pp.615-625
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• 2009

Worldwide inter-operability for microwave access (WiMAX) is a promising technology that provides high data throughput with low delays for various user types and modes of operation. While much research had been conducted on physical and MAC layers, little attention has been paid to a comprehensive and efficient security solution for WiMAX. We propose a hybrid security solution combining identity-based cryptography (IBC) and certificate based approaches. We provide detailed message exchange steps in order to achieve a complete security that addresses the various kind of threats identified in previous research. While attaining this goal, efficient fusion of both techniques resulted in a 53% bandwidth improvement compared to the standard's approach, PKMv2. Also, in this hybrid approach, we have clarified the key revocation procedures and key lifetimes. Consequently, to the best of knowledge our approach is the first work that unites the advantages of both techniques for improved security while maintaining the low overhead forWiMAX.

• 한국중재학회지:중재연구
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• 제9권1호
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• pp.367-390
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• 1999

The basic requirements for conducting electronic commerce include confidentiality, integrity, authentication and authorization. Cryptographic algorithms, make possible use of powerful authentication and encryption methods. Cryptographic techniques offer essential types of services for electronic commerce : authentication, non-repudiation. The oldest form of key-based cryptography is called secret-key or symmetric encryption. Public-key systems offer some advantages. The public key pair can be rapidly distributed. We don't have to send a copy of your public key to all the respondents. Fast cryptographic algorithms for generating message digests are known as one-way hash function. In order to use public-key cryptography, we need to generate a public key and a private key. We could use e-mail to send public key to all the correspondents. A better, trusted way of distributing public keys is to use a certification authority. A certification authority will accept our public key, along with some proof of identity, and serve as a repository of digital certificates. The digital certificate acts like an electronic driver's license. The Korea government is trying to set up the Public Key Infrastructure for certificate authorities. Both governments and the international business community must involve archiving keys with trusted third parties within a key management infrastructure. The archived keys would be managed, secured by governments under due process of law and strict accountability. It is important that all the nations continue efforts to develop an escrowed key in frastructure based on voluntary use and international standards and agreements.

• 한국정보과학회논문지:정보통신
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• 제36권6호
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• pp.545-551
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• 2009

본 논문에서는 USN과 기존 네트워크간 연동을 위한 보안키 관리 프레임워크를 제안한다. USN과 기존 네트워크간 연동은 다양하고 많은 디바이스로 구성되기 때문에, 인증기관(Certificate Authority, CA)의 부재에도 불구하고 공개키 기반의 암호기술이 사용되어야 한다. 제안된 메커니즘은 IP 네트워크의 PKI 시스템의 지원을 받지 못하는 상황에서의 공개키/개인키 관리와 디바이스간 인증에 초점을 두고 있으며, 인증기관 부재의 문제를 해결하기 위해 신원기반 암호화 개념을 도입하였다. 또한, 실제 네트워크에서의 적용가능성 검증에 초점을 두어 USN과 IP 네트워크 그리고 PLC네트워크를 연동하여 테스트베드를 구축하고, 제안 메커니즘을 적용하여 테스트하였다. 이러한 테스트를 통해 보안키 생성, 업데이트 과정에서 대칭키 기반 알고리즘과 유사한 성능을 확인하였고, 네트워크연동 및 장비인증이 가능함을 화인하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권7호
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• pp.2532-2553
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• 2014

In Asiacrypt 2003, Al-Riyami and Paterson proposed the notion of certificateless cryptography, a technique to remove key escrow from traditional identity-based cryptography as well as circumvent the certificate management problem of traditional public key cryptography. Subsequently much research has been done in the realm of certificateless encryption and signature schemes, but little to no work has been done for the identification primitive until 2013 when Chin et al. rigorously defined certificateless identification and proposed a concrete scheme. However Chin et al.'s scheme was proven in the random oracle model and Canetti et al. has shown that certain schemes provable secure in the random oracle model can be insecure when random oracles are replaced with actual hash functions. Therefore while having a proof in the random oracle model is better than having no proof at all, a scheme to be proven in the standard model would provide stronger security guarantees. In this paper, we propose the first certificateless identification scheme that is both efficient and show our proof of security in the standard model, that is without having to assume random oracles exist.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권11호
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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.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권12호
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• pp.3352-3365
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• 2012

Group key agreement (GKA) is a cryptographic primitive allowing two or more users to negotiate a shared session key over public networks. Wu et al. recently introduced the concept of asymmetric GKA that allows a group of users to negotiate a common public key, while each user only needs to hold his/her respective private key. However, Wu et al.'s protocol can not resist active attacks, such as fabrication. To solve this problem, Zhang et al. proposed an authenticated asymmetric GKA protocol, where each user is authenticated during the negotiation process, so it can resist active attacks. Whereas, Zhang et al.'s protocol needs a partially trusted certificate authority to issue certificates, which brings a heavy certificate management burden. To eliminate such cost, Zhang et al. constructed another protocol in identity-based setting. Unfortunately, it suffers from the so-called key escrow problem. In this paper, we propose the certificateless authenticated asymmetric group key agreement protocol which does not have certificate management burden and key escrow problem. Besides, our protocol achieves known-key security, unknown key-share security, key-compromise impersonation security, and key control security. Our simulation based on the pairing-based cryptography (PBC) library shows that this protocol is efficient and practical.

• 융합보안논문지
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• 제15권5호
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• pp.3-8
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• 2015

모바일 클라우드 컴퓨팅 시스템은 일반적으로 데이터 보호와 상호 인증을 위하여 공개키 암호화 기법을 사용하고 있는데 최근 전통적인 공개키 암호화 기술의 변형인 ID-기반 암호화(IBC)가 주목받고 있다. IBC의 증명서-무통제 접근은 클라우드 환경의 동적인 성격에 더 적합하지만, 모바일 장치에 대하여 처리 오버헤드를 최소화하는 보안 프레임워크가 필요하다. 본 논문에서는 모바일 클라우드 컴퓨팅에서의 계층적 ID-기반 암호화(HIBE)의 사용을 제안한다. HIBE는 사용자 인증과 개인키 생성 등의 권한을 위임하여 최상위 공개키 생성기의 업무량을 감소시킬 수 있으므로 모바일 네트워크에 적합하다. 모바일 클라우드 시스템에서 ID-기반 인증과 ID-기반 신분확인 기법을 제안하고, 또한 안전한 데이터처리를 위한 ID-기반 인증 스킴에 대하여 기술하였다. 제안된 스킴은 단방향 해쉬 함수와 XOR 연산으로 설계하여 모바일 사용자를 위한 저 계산 비용을 갖는다.