• Journal of Magnetics
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• v.21 no.4
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• pp.503-508
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• 2016

The roll- and pitch-induced eddy currents create a magnetic field that contributes to the total magnetic signature of naval vessels. The magnetic signature is of concern, as it exposes the ship to the threat of modern influence mines. It is estimated that the eddy current is the second most important source contributing to a ship's underwater magnetic field following the ferromagnetic effect. In the present paper, the finite element (FE) method is used to predict the eddy current signature of a real ship. The FE model is validated using the measurements of the Canadian research vessel CFAV QUEST at the Earth's Field Simulator (EFS) in Schirnau, Germany. Modeling and validation of the eddy current magnetic signature for a real ship represents a novelty in the field. It is shown that the characteristics of this signature depend on frequency. Based on these results, a ship's degaussing system could be improved to cancel both the ferromagnetic and the eddy current contribution to the magnetic signature simultaneously, reducing the susceptibility to sea mines.

• The Journal of Society for e-Business Studies
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• v.21 no.1
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• pp.105-118
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• 2016

Game companies are frequently attacked by attackers while the companies are servicing their own games. This paper analyzes the limit of the Signature detection method, which is a way of detecting hacking modules in online games, and then this paper proposes the Scoring Signature detection scheme to make up for these problems derived from the limits. The Scoring Signature detection scheme enabled us to detect unknown hacking attacks, and this new scheme turned out to have more than twenty times of success than the existing signature detection methods. If we apply this Scoring Signature detection scheme and the existing detection methods at the same time, it seems to minimize the inconvenient situations to collect hacking modules. And also it is expected to greatly reduce the amount of using hacking modules in games which had not been detected yet.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.15
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• pp.211-238
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• 2001

This article discusses and analyses several issues regarding to the Electronic Signature and the Electronic Certification. The objects of the analyse are the each paragraphs of the Korean Electronic Signature Act of 1999 and that of the Korean Electronic Transaction Basic Act of 1999 in comparing to the paragraphs of the Electronic Signatures in Global and National Commerce Act' (E-Sign) of 2000, U.S.A. and that of the Draft UNCITRAL Model Law on Electronic Signature of 2000. The main issues discussed herein are the scope of the electronic signature, the definition of the electronic signature, permission of services to the non-authorized certification service providers, the effect of the electronic signature, the liability of the concerning parties of the electronic signature including liability of the certification service providers, that of the subscribers and that of the relying parties. This paper also discusses the problems of the possibility of issuing the electronic negotiable commercial papers, the validity of the electronic signatures done by electronic agents, the authority certificate, mutual certification of the foreign certification service providers, the permission of the electronic notary service, the problems of the consumer protection and the possibility of issuing electronic insurance policy, etc. The writer concludes by suggesting some measures that will activate the use of electronic signatures under the korean circumstances.

• 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.

• KIISE Transactions on Computing Practices
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• v.20 no.11
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• pp.586-591
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• 2014

In recent years, we can access to video contents anywhere and at any time. Therefore distributed video is easily copied, transformed and republished. Since it brings copyright problem, similarity/duplicate detection and measurement is essential to identify the excessive content duplication. In this paper, we analysed various discernment of video which has been transformed with various ways using MPEG-7 Video Signature. MPEG-7 Video Signature, one of video copy detection algorithms, is block based abstraction. Thus we assume Video Signature is weak for spatial transform. The experiments show that MPEG-7 Video Signature is very weak for spatial transform which could occur general as we have assumed.

• 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.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.4
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• pp.870-879
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• 1997

At crypto'89 meeting, D. chaum suggested an undeniable signature scheme. Undeniable signatures are verified via a protocol between the signer and verifier, so the cooperation of the signer is necessary. So far, ther have been several variants of undeniable signatures to obtain a signature scheme, which can control the abous of ordinary digital signatures. In this paper we integrate these variants into a generalized undeniable-type signature scheme. Also, it will be pointed out, that undeniable signature schemes but its first realization are vulnerable in full view of eavesdropping third party. Moreover, to solve this problem, we propose a new type of digital signature, called "result-indisting-uishable undeniable signature" and construct a practical protocol that implements it.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.9 no.2
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• pp.13-24
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• 1999

Electronic cash is a digital signature issued by bank. If the concept of the distributed secret sharing and magic ink signature is introduced in the existing electronic cash system we can increase the security level and the availability of electronic cash system and trace the electronic cash itself and the owner of electronic cash which was issued anonymously to a user in case of illegal usage of electronic cash by users. If the trust is concentrated on one bank system. the problem of misuse of bank can be occurred. To solve this problem, the distributed secrete sharing scheme need to be introduced in electronic cash system. In this paper We propose a DSS(Digital Signature Standard) distributed magic ink signature scheme and a KCDSA(Korea Certificate-based Digital Signature Algorithm) distributed magic ink signature scheme using a verifiable secret sharing method. and we compare two methods with respect to the required computation amount for the generation of magic-ink signature.

• Journal of Broadcast Engineering
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• v.14 no.3
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• pp.288-298
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• 2009

In this paper, we propose a scheme to associate content-based video signature with Universal Content Identifier (UCI) system of broadcast content for copyright identification and management. Note that content-based video signature can identify a previously distributed content since it is directly extracted from content itself without allocation process of identifier such as UCI. Thus, we design the schema of UCI application metadata, which provides a video signature in order to consistently maintain a systemic link between UCI and the video signature. Also, we present the scenarios of copyright identification, management and additional service, which are based on transmission and management mechanism of video signature with UCI identification system.

• The Journal of the Korea Contents Association
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• v.11 no.1
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• pp.42-49
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• 2011

Proxy signature schemes are configured as proxy signers on behalf of their original signers can be allowed to sign messages. Basic security requirements of proxy signature schemes include the strong unforgeability and the verifiability of delegation. So far, a variety of proxy signature schemes that proved on individual basic security terms but not proved on compounded security terms are proposed. Especially the proposed proxy signature schemes based on RSA problem are proved vulnerable to an attacker with his own private key in terms of the impersonating attack. A unauthorized attacker can generate the proxy signature without the appointee's consent or authorization. In this paper, we propose a proxy signature scheme based on RSA problems and warrants that can be proved the security against the impersonating attack. The proposed proxy signature scheme is analyzed on the safety and compared in terms of efficiency with other proxy signature schemes.