• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권12호
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• pp.6243-6259
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• 2019

As a foundation of next-generation air transportation systems, automatic dependent surveillance-broadcast (ADS-B) helps pilots and air traffic controllers create a safer and more efficient national airspace system. Owing to the open communication environment, it is easy to insert fake aircraft into the system via spoofing or the insertion of false messages. Efforts have thus been made in academic research and practice in the aviation industry to ensure the security of transmission of messages of the ADS-B system. An identity-based batch verification (IBV) scheme was recently proposed to enhance the security and efficiency of the ADS-B system, but current IBV schemes are often too resource intensive because of the application of complex hash-to-point operations or bilinear pairing operations. In this paper, we propose a lightweight IBV signature scheme for the ADS-B system that is robust against adaptive chosen message attacks in the random oracle model, and ensures the security of batch message verification and against the replaying attack. The proposed IBV scheme needs only a small and constant number of point multiplication and point addition computations instead of hash-to-point or pairing operations. Detailed performance analyses were conducted to show that the proposed IBV scheme has clear advantages over prevalent schemes in terms of computational cost and transmission overhead.

• 한국정보통신학회논문지
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• 제11권2호
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• pp.301-308
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• 2007

본 논문에서는 Bilinear Pairing을 사용한 효율적인 신원기반 다중 수신자 암호 기법을 제 안 한다. 제안 기법은 암호화 과정에서 Pairing 연산을 필요로 하지 않으며 복호화 과정에서 단 한번의 Pairing 연산만을 요구한다. 뿐만 아니라, 제안기법을 이용하여 Subset-Cover framework 기반의 효율적인 스테이트리스 (stateless) 공개키 브로드캐스트 암호 기법을 제시한다.

• ETRI Journal
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• 제34권3호
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• pp.421-428
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• 2012

An aggregate signature scheme is a digital signature scheme that allows aggregation of n distinct signatures by n distinct users on n distinct messages. In this paper, we present an aggregate signcryption scheme (ASC) that is useful for reducing the size of certification chains (by aggregating all signatures in the chain) and for reducing message size in secure routing protocols. The new ASC scheme combines identity-based encryption and the aggregation of signatures in a practical way that can simultaneously satisfy the security requirements for confidentiality and authentication. We formally prove the security of the new scheme in a random oracle model with respect to security properties IND-CCA2, AUTH-CMA2, and EUF-CMA.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권12호
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• pp.6214-6242
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• 2019

Routing in mobile ad hoc networks is performed in a distributed fashion where each node acts as host and router, such that it forwards incoming packets for others without relying on a dedicated router. Nodes are mostly resource constraint and the users are usually inclined to conserve their resources and exhibit selfish behaviour by not contributing in the routing process. The trust and reputation models have been proposed to motivate selfish nodes for cooperation in the packet forwarding process. Nodes having bad trust or reputation are detected and secluded from the network, eventually. However, due to the lack of proper identity management and use of non-persistent identities in ad hoc networks, malicious nodes can pose various threats to these methods. For example, a malicious node can discard the bad reputed identity and enter into the system with another identity afresh, called whitewashing. Similarly, a malicious node may create more than one identity, called Sybil attack, for self-promotion, defame other nodes, and broadcast fake recommendations in the network. These identity-based attacks disrupt the overall detection of the reputation systems. In this paper, we propose a reputation-based scheme that detects selfish nodes and deters identity attacks. We address the issue in such a way that, for normal selfish nodes, it will become no longer advantageous to carry out a whitewash. Sybil attackers are also discouraged (i.e., on a single battery, they may create fewer identities). We design and analyse our rationale via game theory and evaluate our proposed reputation system using NS-2 simulator. The results obtained from the simulation demonstrate that our proposed technique considerably diminishes the throughput and utility of selfish nodes with a single identity and selfish nodes with multiple identities when compared to the benchmark scheme.

• 정보보호학회논문지
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• 제1권1호
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• pp.3-15
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• 1991

shamir는 공개키 저장을 위한 키 디렉토리(Key directory)의 유지가 요구되지 않는 ID(Identity)기본 암호 시스팀 및 디지틀 서명 방식의 개념을 1984년 제안하였다. 본 논문에서는 지금까지 발표된 대표적인 공개키 암호알고리즘(RSA, Merkle-Hellman, El-Gamal 암호알고리즘) 등을 바탕으로 이 산대수문제에 기반을 둔 ID기본 디지틀 서명방식을 제안하고 이에 대한 가능한 여러 공격 형태들을 분석함으로서 안전성(security)을 입증한다. 그리고 ID 기본 암호시스팀과 디지틀 서명방식의 특징을 제시한다.

• 대한수학회보
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• 제46권4호
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• pp.743-769
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• 2009

An ID-based DNF signature scheme is an ID-based signature scheme with an access structure which is expressed as a disjunctive normal form (DNF) with literals of signer identities. ID-based DNF signature schemes are useful to achieve not only signer-privacy but also a multi-user access control. In this paper, we formally define a notion of a (non-interactive) ID-based DNF signature and propose the first noninteractive ID-based DNF signature schemes that are secure under the computational Diffie-Hellman and subgroup decision assumptions. Our first scheme uses random oracles, and our second one is designed without random oracles. To construct the second one, we use a novel technique that converts a non-interactive witness indistinguishable proof system of encryption of one bit into a corresponding proof system of encryption of a bit-string. This technique may be of independent interest. The second scheme straightforwardly yields the first ID-based ring signature that achieves anonymity against full key exposure without random oracles. We finally present two extensions of the proposed ID-based DNF signature schemes to support multiple KGCs and different messages.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권6호
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• pp.3299-3315
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• 2019

Deniable authentication (DA) is a protocol in which a receiver can generate an authenticator that is probabilistically indistinguishable from a sender. DA can be applied in many scenarios that require user privacy protection. To enhance the security of DA, in this paper, we construct a new deniable authenticated encryption (DAE) scheme that realizes deniable authentication and confidentiality in a logical single step. Compared with existing approaches, our approach provides proof of security and is efficient in terms of performance analysis. Our scheme is in an identity-based environment; thus, it avoids the public key certificate-based public key infrastructure (PKI). Moreover, we provide an example that shows that our protocol is applicable for e-voting systems.

• 디지털산업정보학회논문지
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• 제11권1호
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• pp.59-67
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• 2015

A novel authentication mechanism is biometric authentication where users are identified by their measurable human characteristics, such as fingerprint, voiceprint, and iris scan. The technology of biometrics is becoming a popular method for engineers to design a more secure user authentication scheme. In terms of physiological and behavioral human characteristics, biometrics is used as a form of identity access management and access control, and it services to identity individuals in groups that are under surveillance. In this article, we review the biometric-based authentication protocol by Althobati et al. and provide a security analysis on the scheme. Our analysis shows that Althobati et al.'s scheme does not guarantee server-to-user authentication. The contribution of the current work is to demonstrate this by mounting threat of data integrity and bypassing the gateway node on Althobati et al.'s scheme. In addition, we analysis the security vulnerabilities of Althobati et al.'s protocol.

• 한국컴퓨터정보학회논문지
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• 제27권5호
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• pp.127-138
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• 2022

본 논문에서는 금융권 DID(Decentralized Identity) 서비스 체계의 표준 방식을 준수하는 가운데 체계적인 검증 방식을 통하여 개인 정보나 자격 증명을 유연하게 제어할 수 있는 블록체인 기반의 DID 서비스인 FinDID(Financial Decentralized IDentity)를 제시한다. DID는 특정 인증기관 없이 탈중앙화 환경에서 활용하는 신원 관리 체계이며, 사용자가 자신의 정보를 제어할 수 있는 기술로서 사용자 자신의 개인정보에 대한 자기 주권화를 실현할 수 있다. FinDID을 통하여 사용자는 자신의 여러 개인정보를 인증하는 크리덴셜을 발급자에게 발급받아 개인 전자지갑을 이용해 타겟금융 서비스가 필수적으로 요구하는 클레임만을 크리덴셜에서 선택하여 프레젠테이션을 생성하고, 이를 금융 서비스에게 제출하여 자신의 서비스 이용자격을 부여받는다. FinDID는 전자지갑, 크리덴셜 발급자, 크리덴셜 저장소 그리고 DID 관리 컨트랙트 및 크리덴셜 관리 컨트랙트를 포함하는 DID 서비스 및 이러한 서비스 체계를 이용하는 금융서비스로 구성된다. DID 서비스는 각 사용자의 DID를 관리하고 관련된 신원 관리체계의 모든 검증과정을 지원한다.

• 전자공학회논문지CI
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• 제46권1호
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• pp.64-77
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• 2009

ID기반 재암호화 기법(ID-based foxy re-encryption scheme)은 사용자 간의 복호 능력 위임을 가능하게 하며 분산 데이터 저장, DRM, 이메일 전달 시스템 등의 다양한 분산 암호시스템을 위해 활발히 연구되고 있다. 최근 재암호화키 생성의 비상호성(Non-interactivity)을 제공하는 기법이 Green과 Ateniese에 의해 제안되었다. 이 기법은 선택 암호문 공격에 대한 안전성을 제공하기 위해 설계되었다. 본 논문에서는 Green-Ateniese ID기반 재암호화 기법이 근본적으로 사용자 키 노출 공격에 취약함을 보이고 선택 암호문 공격에 대한 안전성이 보장되지 않음을 증명한다. 그리고 이러한 보안 취약점을 해결하는 새로운 두 가지 ID기반 재암호화 기법들을 제안한다. 제안 기법들이 랜덤 오라클 모델(Random Oracle Model)에서 단순 평문 공격과 선택 암호문 공격에 대해 각각 안전함을 증명한다. 선택 암호문 공격에 안전한 제안 기법을 구성하기 위해, 본 논문에서는 최초로 짧은 서명에 기반한 자가 인증 기법을 고안하여 적용한다. 제안 기법의 중요한 특징은 재암호화 후 암호문의 구조가 유지되는 것이다. 따라서 이전 기법들과는 대조적으로 암호문 확장이 발생되지 않는다. 또한 재암호화의 횟수에 제한이 없어서 연속적인 암호문 변환이 가능하여 다중의 사용자를 위한 복호 능력 위임을 구현할 수 있다.