• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.10
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• pp.5219-5243
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• 2019

In electronic ticketing system, the malicious behavior of scalpers damages the customer's interest and disturbs the normal order of market. In order to solve the problem of scalpers, we took two steps. Firstly, we established the electronic ticketing system based on the consortium blockchain (CB-ETS). By establishing CB-ETS, we can make the ticketing market develop better in a controlled environment and be managed by the members in the consortium blockchain. Secondly, we put forward a kind of taxation mechanism for suppressing scalpers based on CB-ETS. Together with the regulatory mechanism, our scheme can effectively reduce the scalpers' profits and further inhibit scalpers. Through the above two steps, the scheme can effectively resist the malicious behavior of scalpers. Among them, in the process of transferring tickets, we optimized the transfer mechanism to achieve a win-win situation. Finally, we analyzed the security and efficiency of our scheme. Our scheme realizes the anonymity through the mixed currency protocol based on ring signature and guarantees the unforgeability of tickets by multi-signature in the process of modifying the invalidity of tickets. It also could resist to Dos attacks and Double-Spending attacks. The efficiency analysis shows that our scheme is significantly superior to relevant works.

• 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 the Korea Convergence Society
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• v.9 no.11
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• pp.75-81
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• 2018

Anonymity and privacy issues are becoming important as all transactions in the blockchain are open to users. Public blockchains appear to guarantee anonymity by using public-key addresses on behalf of users, but they can weaken anonymity by tracking with various analytic techniques based on transaction graph. In this paper, we propose a scheme to protect anonymity and privacy by converging various security techniques such as k-anonymity, mixing, blind signature, multi-phase processing, random selection, and zero-knowledge proof techniques with incentive mechanism and contributor participation. Through performance analysis, our proposed scheme shows that it is difficult to invade privacy and anonymity through collusion attacks if the number of contributors is larger than that of conspirators.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.9
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• pp.1295-1303
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• 1993

We present an 1-out-of-n noninteractive OT(Oblivious Transfer) protocol based on the Diffle-Hellman assumption and a new fair exchange scheme of secret information among multi-users. Using the noninteractive OT protocol and the fair exchange scheme, we also present a new digital multisignature scheme based on Fiat-Shamir signature scheme and analyze its security. Owing to its concurrency, viability, and dishonesty detectablility, the proposed digital multisignature scheme is applicable to electronic multi-user contract systems.

• ETRI Journal
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• v.41 no.6
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• pp.863-872
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• 2019

Elliptic curve cryptography is a relatively lightweight public-key cryptography method for key generation and digital signature verification. Some lightweight curves (eg, Curve25519 and Curve Ed448) have been adopted by upcoming Transport Layer Security 1.3 (TLS 1.3) to replace the standardized NIST curves. However, the efficient implementation of Curve Ed448 on Internet of Things (IoT) devices remains underexplored. This study is focused on the optimization of the Curve Ed448 implementation on low-end IoT processors (ie, 8-bit AVR and 16-bit MSP processors). In particular, the three-level and two-level subtractive Karatsuba algorithms are adopted for multi-precision multiplication on AVR and MSP processors, respectively, and two-level Karatsuba routines are employed for multi-precision squaring. For modular reduction and finite field inversion, fast reduction and Fermat-based inversion operations are used to mitigate side-channel vulnerabilities. The scalar multiplication operation using the Montgomery ladder algorithm requires only 103 and 73 M clock cycles on AVR and MSP processors.

• Journal of Information Processing Systems
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• v.10 no.4
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• pp.555-567
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• 2014

Biometric performance improvement is a challenging task. In this paper, a hierarchical strategy fusion based on multimodal biometric system is presented. This strategy relies on a combination of several biometric traits using a multi-level biometric fusion hierarchy. The multi-level biometric fusion includes a pre-classification fusion with optimal feature selection and a post-classification fusion that is based on the similarity of the maximum of matching scores. The proposed solution enhances biometric recognition performances based on suitable feature selection and reduction, such as principal component analysis (PCA) and linear discriminant analysis (LDA), as much as not all of the feature vectors components support the performance improvement degree.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04b
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• pp.52-54
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• 2004

모바일 환경에서 효과적인 데이터 전송 방법인 브로드 캐스트 기법에서 중요한 문제 중의 하나가 데이터에 대한 인덱스 생성이다. 데이터에 대한 인덱스가 제공되면 클라이언트는 튜닝 타임과 엑세스 타임을 줄일 수 있고, 그와 함께 배터리 소모도 줄일 수 있다 기존에 제시된 인덱스 생성 기법온 대부분 트리 구조를 기반으로 하고 있다. 트리 기반 인덱싱 기법은 튜닝 타임을 최소화하지만, 반면 멀티-어트리뷰트(multi-attribute)에 대한 엑세스나 다양한 종류의 멀티미디어 데이터들 혹은 클러스터링 된 데이터에 대한 인덱스 생성이 어렵다. 이러한 문제를 해결하기 위해 시그너쳐 기반의 인덱싱 기법이 제시되었다. 그러나 기존의 시그너쳐 기반 인덱싱 기법에서는 엑세스 타임이 전체 브로드 캐스트 타임으로 고정되는 문제가 있었다. 본 논문비서는 앞으로 브로드 캐스팅 될 데이터들에 대한 포괄적인 정보를 가지는 시그너쳐 집합을 인덱스로 제공해서 클라이언트의 엑세스 타임을 최소화시키는 시그너쳐 스킴을 제시한다.

• The KIPS Transactions:PartC
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• v.10C no.6
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• pp.747-754
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• 2003

Thia paper suggests a milti user-authentication system comprises that DNA biometric informatiom, owner's RFID(Radio Frequency Identification) smartcard of hardware token, and PKI digital signqture of software. This system improved items proposed in [1] as follows : this mechanism provides one RFID smartcard instead of two user-authentication smartcard(the biometric registered seal card and the DNA personal ID card), and solbers user information exposure as RFID of low proce when the card is lost. In addition, this can be perfect multi user-autentication system to enable identification even in cases such as identical twins, the DNA collected from the blood of patient who has undergone a medical procedure involving blood replacement and the DNA of the blood donor, mutation in the DNA base of cancer cells and other cells. Therefore, the proposed system is applied to terminal log-on with RFID smart card that stores accurate digital DNA biometric information instead of present biometric user-authentication system with the card is lost, which doesn't expose any personal DNA information. The security of PKI digital signature private key can be improved because secure pseudo random number generator can generate infinite one-time pseudo randon number corresponding to a user ID to keep private key of PKI digital signature securely whenever authenticated users access a system. Un addition, this user-authentication system can be used in credit card, resident card, passport, etc. acceletating the use of biometric RFID smart' card. The security of proposed system is shown by statistical anaysis.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.2
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• pp.647-669
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• 2016

Multiple attribute for decision making including user preference will increase the complexity of route selection process. Various approaches have been proposed to solve the optimal route selection problem. In this paper, multi attribute decision making (MADM) algorithms such as Simple Additive Weighting (SAW), Weighted Product Method (WPM), Analytic Hierarchy Process (AHP) method and Total Order Preference by Similarity to the Ideal Solution (TOPSIS) methods have been proposed for acoustic signature based optimal route selection to facilitate user with better quality of service. The traffic density state conditions (very low, low, below medium, medium, above medium, high and very high) on the road segment is the occurrence and mixture weightings of traffic noise signals (Tyre, Engine, Air Turbulence, Exhaust, and Honks etc) is considered as one of the attribute in decision making process. The short-term spectral envelope features of the cumulative acoustic signals are extracted using Mel-Frequency Cepstral Coefficients (MFCC) and Adaptive Neuro-Fuzzy Classifier (ANFC) is used to model seven traffic density states. Simple point method and AHP has been used for calculation of weights of decision parameters. Numerical results show that WPM, AHP and TOPSIS provide similar performance.

• Journal of the Korea Society of Computer and Information
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• v.10 no.4 s.36
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• pp.77-85
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• 2005

Digital copyright protection is important in the protective side of effort to have leaned to in property right and it which are intelligent of an author and is very important for development of digital contents industry. It is the misgovernment that a reproduction is easy as for the digital contents. and the original and a copy have the same characteristic, and it is so, and is experiencing what is hard for protection of copyright and large quantity illegal copy and illegal distribution prevention. CDN needs a copyright protective plan about the digital contents that digital contents providers were written jointly. The paper used a non-repudiation multi-technique for copyright protection about the digital contents which were written jointly. The Non-repudiation multi-technique proved efficiency about this.