• Journal of the Korea Institute of Information Security & Cryptology
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• v.1 no.1
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• pp.3-15
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• 1991

in 1984 Shamir proposed the concept of ID(identity)-based cryptosystem and digital signature scheme wich does not require any public file for storing the user' s public keys. In this paper, the concept of the ID-based cryptosystem based on discrete logarithm problem using the conven-tional public-key cryptosystems is described, and the implementation method of the ID-based cryptosystem is also presented. The new digital signaturw schme based on the ID-based crypto-system is proposed and possible atacks are considered and analyzed for the security of digital signature scheme. The proposed ID-based schemes are particularrly useful for smart card and personal identification card application.

• Journal of KIISE:Information Networking
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• v.31 no.4
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• pp.405-413
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• 2004

Design an efficient and secure electronic payment system is important for M-Commerce. In this paper, we propose an efficient Micro-Payment Protocol that allows multiple transactions using ID-based public key cryptosystem. Current PayWord system requires to generate certificate of the vendor for each transaction. In this paper, we use a session key instead of certificate key generated by Weil Pairing which use an Elliptic Curve Cryptosystem over finite field $F_q$ for transactions Therefore, it is more secure in Known key attacks as well as Man-in-the-middle attacks.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.5
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• pp.165-176
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• 2004

Al-Riyami and Paterson$^{[1]}$ suggested the new public key paradigm which is called the certificateless public key system. This system takes the advantages of both traditional PKC and ID-based PKC. It does not require the use of certificates of the public key and does not have the key escrow problem caused from the ID-based cryptosystem. In this paper, we propose an efficient certificateless public key encryption scheme which satisfies mutual authentication. The security of our protocol is based on the hardness of two problems; the computational Diffie-Hellman problem(CDHP) and the bilinear Diffie-Hellman problem(BDHP). We also give a formal security model for both confidentiality and unforgeability, and then show that our scheme is probably secure in the random oracle model.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.2C
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• pp.348-353
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• 2004

Development of an efficient and secure payment system is prerequisite for the construction of electronic payment mechanism in mobile environment. Since current PayWord protocol system generates vendor's certificate for each transaction, it requires lot of operation for transaction. In this paper, we use a session key generated by ID-based tripartite Key agreement protocol which use an Elliptic Curve Cryptosystem over finite field $F_{q}$ for transactions. Therefore, our protocol reduces algorithm operations. In particular, proposed protocol using ID-based public key cryptosystem has the advantages over the existing systems in speed and it is more secure in Man-in-the-middle attacks and Forward secrecy.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.6
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• pp.1109-1122
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• 2016

Certificateless public key cryptography is a technique that can solve the certificate management problem of a public key cryptosystem and clear the key escrow issue of ID-based cryptography using the public key in user ID. Although the studies were actively in progress, many existing schemes have been designed without taking into account the safety of the secret value with the decryption key exposure attacks. If previous secret values and decryption keys are exposed after replacing public key, a valid private key can be calculated by obtaining the partial private key corresponding to user's ID. In this paper, we propose a new security model which ensures the security against the key exposure attacks and show that several certificateless public key encryption schemes are insecure in the proposed security model. In addition, we design a certificateless public key encryption scheme to be secure in the proposed security model and prove it based on the DBDH(Decisional Bilinear Diffie-Hellman) assumption.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.6 no.3
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• pp.57-70
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• 1996

It would be desirable in network to implement an efficient asymmetric key cryptosystem which can not only solve the public key authentication problem but also integrate digital signature and key distribution, We propose two ID-based key distribution systems integrated with digital signature, and analyze them in computation and implementation. The first is based on the EIGamal-typed signature scheme, and the second is based on the RSA scheme, Both can be employed in one-pass and interactive key distribution systems.

• Convergence Security Journal
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• v.8 no.2
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• pp.1-6
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• 2008

Designing efficient and secure electronic payment is important for M-Commerce. In this paper, we propose an efficient Micro-payment protocol that allows multiple transactions using ID-based public key encryption-system. The proposed payword system requires to generate authenticated key generated by Weil-pairing which uses an elliptic curve cryptosystem over finite field Fq for transactions. Therefore, it is more secure in known key attacks as well as man-in-the middle attacks.

• 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.

• Convergence Security Journal
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• v.12 no.6
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• pp.39-50
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• 2012

Battlefield management systems are operated by the Public Key Infrastructure (PKI) and cryptographic equipment is distributed through the personal delivery to the enemy has deodorizing prone to structure. In addition, Per person each battlefield management system (C4I) encryption key operate and authentication module to manage multiple encryption so, encryption key operating is restrictions. Analysis of the problems of this public key infrastructure(PKI), Identity-Based Cryptosystem(IBC) and Attribute-Based Cryptosystem(ABC) to compare construct the future of encrypt ion and authentication system were studied. Authentication method for the connection between the system that supports data encryption and secure data communication, storage, and communication scheme is proposed.

• The Journal of the Korea Contents Association
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• v.6 no.12
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• pp.12-20
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• 2006

In this paper, we propose electronic payment protocol using GDHP blind signature scheme to activate e-business in the wire/wireless integrated environment. The protocol applied elliptic curve algorithm on the GDHP base and improved the efficiency of the existing blind signature technique on the basis of communication frequency and calculation number. And the protocol accelerated speed and strengthened safety against man-in-the-middle attacks and forward secrecy because the certification between individuals is performed by the session key created by Weil paring using elliptic curve cryptosystem in the limited entity $F_q$ instead of the certification used in the existing PayWord protocol.