• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.3
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• pp.129-134
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• 2003

Hierarchical ID-based Cryptography proposed by C. Gentry and A. Silverberg has the problem that the length of the ciphertext is proportional to the depth of the recipient in the hierarchy. In this paper, we propose the new methods to shorten the length of the ciphertext by using HlDS(Hierarchical ID-based Signature).

• The Journal of the Korea Contents Association
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• v.19 no.7
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• pp.421-426
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• 2019

Nowadays, various type of technologies are used for user authentication, such as knowledge based(ID/PW, etc.) authentication, biometric based(Iris/fingerprint/vein recognition) authentication, ownership based(OTP, security card, etc.) authentication. ID/PW authentication technology, a knowledge based authentication, despite the advantages of low in implementation and maintenance costs and being familiar to users, there are disadvantages of vulnerable to hacking attacks, Other authentication methods solve the vulnerability in ID/PW authentication technology, but they have high initial investment cost and maintenance cost and troublesome problem of reissuance. In this paper, we proposed to improve security and convenience over existing ID/PW based authentication technology, and to secure user authentication without restriction on the devices used for authentication.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.3
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• pp.1289-1310
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• 2016

Dynamic ID-based authentication solves the ID-theft problem by changing the ID in each session instead of using a fixed ID while performing authenticated key exchanges between communicating parties. User anonymity is expected to be maintained and the exchanged key kept secret even if one of the long-term keys is compromised in the future. However, in the conventional dynamic ID-based authentication scheme, if the server's long-term key is compromised, user anonymity can be broken or the identities of the users can be traced. In addition, these schemes are vulnerable to replay attacks, in which any adversary who captures the authentication message can retransmit it, and eventually cause the legitimate user to be denied service. This paper proposes a novel dynamic ID-based authentication scheme that preserves forward anonymity as well as forward secrecy and obviates replay attacks.

• Bulletin of the Korean Mathematical Society
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• v.46 no.4
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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.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.19 no.5
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• pp.25-34
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• 2009

Many conference systems over the Internet require authenticated group key agreement (AGKA) for secure and reliable communication. After Shamir [1] proposed the ID-based cryptosystem in 1984, ID-based AGKA protocols have been actively studied because of the simple public key management. In 2006, Zhou et al. [12] proposed two-round ID-based AGKA protocol which is very efficient in communication and computation complexity. However, their protocol does not provide user identification and suffers from the impersonation attack by malicious participants. In this paper, we propose improved ID-based AGKA protocol to prevent impersonation attack from Zhou et al.'s protocol. In our protocol, the malicious insider cannot impersonate another participants even if he knows the ephemeral group secret value. Moreover, our protocol reduces the computation cost from Zhou et al.'s protocol.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.4 no.2
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• pp.90-118
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• 1994

본 논문에서는 certificatoin-based 방식이 아닌 id-based방식이면서도 사용자가 자신의 비밀키를 선택할 수 있는 역설적인 id-based 방식을 제안한다. 제안한 방식은 Girault가 제안한 self-certified공개키 개념을 id-based방식에 적용한 것이다. 제안한 방식의 안전성은 고차잉여류 문제와 이산대수 문네에 기반을 두고 있다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.6
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• pp.124-136
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• 2019

Autonomous driving at intersections requires assistance by exchanging traffic information between traffic objects due to the intersection of various vehicles and complicated driving environment. For this reason, traffic information exchange between adjacent intersections is required, but the node ID representing the intersection in the Korean standard node link system have limitations in updating intersections and identifying location information of intersections through IDs due to the configuration system including serial numbers. In this paper, we designed a coordinate-based intersection ID configuration system created by processing and merging two-dimensional coordinates of intersections to include location information in the intersection ID. In order to verify the applicability of the proposed intersection ID, we applied a new intersection ID to domestic intersections and confirmed that there are no duplicate values. Coordinate-based intersection ID reduces data size by 60% compared to existing node ID, and enables spatial queries such as searching for nearby intersections and extracting intersections in specific areas in the form of boxes without GIS tools. Therefore, coordinate-based intersection ID is expected to be more scalable and utilized than existing node ID.

• Electronics and Telecommunications Trends
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• v.24 no.5
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• pp.133-142
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• 2009

본 고에서는 사용자가 모바일 환경에서 자신의 ID 정보를 효율적으로 공유하기 위한 ID 공유 게이트웨이 기술에 대해 기술하고 있다. ID 공유 게이트웨이는 모바일 환경에서 ID 정보 공유시 문제가 될 수 있는 프로토콜 변환 및 메시지 보안 기능을 전담하여 처리하는 것이 목적이다. 이러한 게이트웨이 기술은 향후 ID 공유 기술을 이용한 다양한 음복함 서비스를 모바일 웹 응용서비스에서도 가능하게 한다는 의미를 가지고 있다.

• Convergence Security Journal
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• v.15 no.5
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• pp.3-8
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• 2015

Most mobile cloud computing system use public key cryptography to provide data security and mutual authentication. A variant of traditional public key technologies called Identity-Based Cryptography(IBC) has recently received considerable attention. The certificate-free approach of IBC may well match the dynamic qualities of cloud environment. But, there is a need for a lightweight secure framework that provides security with minimum processing overhead on mobile devices. In this paper, we propose to use hierarchical ID-Based Encryption in mobile cloud computing. It is suitable for a mobile network since it can reduce the workload of root Public Key Generators by delegating the privilege of user authentication and private key generation. The Identity-Based Encryption and Identity-Based Signature are also proposed and an ID-Based Authentication scheme is presented to secure data processing. The proposed scheme is designed by one-way hash functions and XOR operations, thus has low computation costs for mobile users.

• ETRI Journal
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• v.36 no.4
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• pp.673-681
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• 2014

Fairness of exchange is a significant property for secure online transactions, and a fair exchange scheme is a useful tool for ensuring the fairness of exchanges conducted over networks. In this paper, we propose an ID-based optimistic fair exchange scheme based on the RSA function, one which is designed by combining a well-known RSA-based signature scheme and the (naive) RSA function. Note that the main contribution of this paper is to give the first provably secure ID-based fair exchange scheme based on the RSA function, whose security can be proved under fully formalized security models. Our scheme has the following additional strongpoints. The scheme is setup-free; hence, there is no registration step between a user and an arbitrator. Moreover, the proposed scheme is designed in an ID-based setting; thus, it is possible to eliminate the need for certificates and avoid some related problems.