• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.3
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• pp.11-25
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• 2011

The Miller algorithm is employed in the typical pairing computation such as Weil, Tate and Ate for implementing ID based cryptosystem. By analyzing the Mrabet's attack that is one of fault attacks against the Miller algorithm, this paper presents au efficient fault attack in Affine coordinate system, it is the most basic coordinates for construction of elliptic curve. The proposed attack is the effective model of a count check fault attack, it is verified to work well by practical fault injection experiments and can omit the probabilistic analysis that is required in the previous counter fault model.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.6
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• pp.149-161
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• 2003

Partially blind signature scheme allows the signer to insert non-removable common information into his blind signature. Blind signatures providing with both users privacy and data authenticity are one of key parts of information systems, such anonymous electronic cash and electronic voting as typical examples. Partially blind signature, with which all expired e-cash but for still-alive can be removed from the banks database, copes well with the problem of unlimited growth of the banks' database in an electronic cash system. In this paper we propose an efficient ID-based partially blind signature scheme using the Weil-pairing on Gap Diffie-Hellman group. The security of our scheme relies on the hardness of Computational Diffie-Hellman Problem. The proposed scheme provides higher efficiency than existing partially blind signature schemes by using three-pass protocol between two participants, the signer and requesters also by reducing the computation load. Thus it can be efficiently used in wireless environment.

• 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 Communications and Networks
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• v.14 no.6
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• pp.682-691
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• 2012

Key agreement protocol is a fundamental protocol in cryptography whereby two or more participants can agree on a common conference key in order to communicate securely among themselves. In this situation, the participants can securely send and receive messages with each other. An adversary not having access to the conference key will not be able to decrypt the messages. In this paper, we propose a novel identity-based authenticated multi user key agreement protocol employing a symmetric balanced incomplete block design. Our protocol is built on elliptic curve cryptography and takes advantage of a kind of bilinear map called Weil pairing. The protocol presented can provide an identification (ID)-based authentication service and resist different key attacks. Furthermore, our protocol is efficient and needs only two rounds for generating a common conference key. It is worth noting that the communication cost for generating a conference key in our protocol is only O($\sqrt{n}$) and the computation cost is only O($nm^2$), where $n$ implies the number of participants and m denotes the extension degree of the finite field $F_{p^m}$. In addition, in order to resist the different key attack from malicious participants, our protocol can be further extended to provide the fault tolerant property.

• Journal of the Korea Society of Computer and Information
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• v.11 no.2 s.40
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• pp.239-251
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• 2006

Zheng's signcryption scheme is a new encryptical scheme of which can save more expense than those of the current signature encryption by using digital signature and symmetric key encryption logically. The current signcryption schemes have a problem that is to be exposed the secret key of the receiver in the case of checking repudiation of origin by the third party. To solve this problem, a solution suggested in this paper is to use multi-purpose ID-based signcryption scheme with anonymity and unlinkability. This solution is safe and more efficient than current signcryption schemes because the suggested scheme keeps the security of the random oracle model as using Weil-pairing in encryption. and follows a formal proof of semantic security of the decisional Diffie-Hellman problem.

• Journal of KIISE:Information Networking
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• v.30 no.6
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• pp.720-728
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• 2003

Blind signature is such a signature scheme that conceals the contents of signature itself and who is the user of the signature make user's anonymity possible. For this reason, they are used in security services such as electronic cashes and electronic votes in which the behavior of actor should not be exposed. In this paper we propose an ID-based blind signature scheme from Gap Diffie-Hellman group. Its security is based on the hardness of Computational Diffie-Hellman Problem. Proposed scheme efficiently improve against existing blind signature scheme by using two-pass protocol between two users and by reducing computation process. Therefore it can be used efficiently in wireless PKI environment.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.12
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• pp.4987-5014
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• 2015

The bilinear pairing, also known as Weil pairing or Tate pairing, is widely used in cryptography and its properties help to construct cryptographic schemes for different applications in which the security of the transmitted data is a major concern. In remote login authentication schemes, there are two major requirements: i) proving the identity of a user and the server for legitimacy without exposing their private keys and ii) freedom for a user to choose and change his password (private key) efficiently. Most of the existing methods based on the bilinear property have some security breaches due to the lack of features and the design issues. In this paper, we develop a new scheme using the bilinear property of an elliptic point and the biometric characteristics. Our method provides many features along with three major goals. a) Checking the correctness of the password before sending the authentication message, which prevents the wastage of communication cost; b) Efficient password change phase in which the user is asked to give a new password after checking the correctness of the current password without involving the server; c) User anonymity - enforcing the suitability of our scheme for applications in which a user does not want to disclose his identity. We use BAN logic to ensure the mutual authentication and session key agreement properties. The paper provides informal security analysis to illustrate that our scheme resists all the security attacks. Furthermore, we use the AVISPA tool for formal security verification of our scheme.

• IEIE Transactions on Smart Processing and Computing
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• v.2 no.5
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• pp.297-301
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• 2013

Key agreement protocols allow multi-parties exchanging public information to create a common secret key that is known only to those entities over an insecure network. Since Joux first published the pairing-based one round tripartite key agreement protocol, many authenticated protocols have been proposed. Unfortunately, many of them have been broken while others have been shown to be deficient in some desirable security attributes. In 2004, Cheng et al. presented two protocols aimed at strengthening Shim's certificate-based and Zhang et al.'s tripartite identity-based protocols. This paper reports that 1) In Cheng et al.'s identity-based protocol, an adversary can extract long-term private keys of all the parties involved; and 2) Cheng et al.'s certification-based protocol is weak against key integrity attacks. This paper suggests possible remedies for the security flaws in both protocols and then presents a modified Cheng et al.'s identity-based, one-round tripartite protocol that is more secure than the original protocol.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2003.07a
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• pp.37-42
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• 2003

Threshold signature and blind signature are playing important roles in cryptography as well as practical applications such as e-cash and e-voting systems. In this paper, we present a new threshold blind digital signature based on pairings without a trusted third party. Our scheme operates on Gap Diffie-Hellman group, where Computational Diffie-Hellman problems are hard but Decision Diffie-Hellman problems are easy. For example, we use pairings that could be built from Weil pairing or Tate pairing. To the best of our knowledge, we claim that our scheme is the first threshold blind signature using pairings with provable security in the random oracle model.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.3C
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• pp.293-298
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• 2008

Recently, with the development of mobile techniques and the consideration to conveniency of using, the research on Mobile RFID Reader technique is getting more and more attentions. Until now, all security authentication algorithms of RFID are algorithms about range between Tag and Reader. The range between Reader and backend DB is composed by wired networks, so it's supposed to be secure range. But it must be taken account of the problem of information security and privacy in wireless range during the design of Mobile RFID Reader. In this paper we design an blind signature scheme based on weil-paring finite group's ECC encryption scheme, and by using this blind signature we propose the anonymous authorization scheme to Mobile RFID Reader's users.