• The Journal of the Korea Contents Association
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• v.4 no.4
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• pp.71-78
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• 2004

Dedicated Short Range Communications(DSRC) as a prominent communications candidate for Intelligent Transportation Systems(ITS) have been developed to support ITS applications such as value-added information service, e-commerce, electronic toll payment, etc. These various applications associated with electronic payment through unsecure communication channel of DSRC suffer from security threats. To ensure secure payment, we have adopted appropriate cryptographic mechanisms including encipherment, authentication exchange and digital signature. The cryptographic mechanisms require to use cryptographic keys established between two communication entities. In this paper, we propose a secure electronic payment system which is designed to have some functions for strong authentication, encryption, key agreement, etc. Especially, we adopt domestic developed cryptographic algorithms such as EC-KCDSA and SEED for digital signature and block cipher, respectively. We can show those mechanisms are appropriate for the secure electronic payment system for ITS services under the DSRC wireless environment in aspects of constrained computational resource use and processing speed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.4
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• pp.479-488
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• 2016

For a secure communication system, it is necessary to use secure cryptographic algorithms and keys. Modern cryptographic system generates high entropy encryption key through standard key derivation functions. Using recent progress in quantum key distribution(QKD) based on quantum physics, it is expected that we can enhance the security of modern cryptosystem. In this respect, the study on the dual key agreement is required, which combines quantum and modern cryptography. In this paper, we propose two key derivation functions using dual key agreement based on QKD and RSA cryptographic system. Furthermore, we demonstrate several simulations that estimate entropy of derived key so as to support the design rationale of our key derivation functions.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.6
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• pp.1224-1228
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• 2003

The use of digital imaging technique and digital contents based on internet has grown rapidly for last several years, and the needs of digital image protection become more important. For the purpose of copyright protection on digital image, the verification of authentication techniques like content authentication, ownership authentication, illegal copy and etc are needs. Digital watermarking, the invisible encryption technique to insert digital watermarking into image, the sophisticated perceptual information should be used for providing transparency and robustness of images on watermarking process. In this paper, we implement the algorithm for preventing forged attack. ownership protection and authentication by transforming the wavelet algorithms in frequency domain in terms of human visual system.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.1
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• pp.96-102
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• 2009

Due to the rapid growth of the Internet, it is possible to distribute the digital content efficiently. However, the need for image data protection and secret communication technique is also on the rise because of an infringement of the copyright by malicious attackers. Shamir and Lin-Tsai proposed simple secret image encryption algorithms based on the principle of secret sharing, respectively. However, their secret sharing schemes have a serious problem which can be declined the image quality and it is possible for third party to know embed information. In this paper, we propose a new secret sharing scheme using gray code that can be increased the image quality and security. As a result of our experiment, the proposed scheme is not only shown of good image quality and but also provide enhanced security compare with Shamir and Lin-Tasi's schemes.

• Journal of the Korea Society of Computer and Information
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• v.17 no.3
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• pp.67-76
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• 2012

Traffic classification plays an important role in traffic management. To traditional methods, P2P and encryption traffic may become a problem. Support Vector Machine (SVM) is a useful classification tool which is able to overcome the traditional bottleneck. The main disadvantage of SVM algorithms is that it's time-consuming to train large data set because of the quadratic programming (QP) problem. However, the useful support vectors are only a small part of the whole data. If we can discard the useless vectors before training, we are able to save time and keep accuracy. In this article, we discussed the feasibility to remove the useless vectors through a sequential method to accelerate training speed when dealing with large scale data.

• Journal of the Korea Convergence Society
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• v.8 no.7
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• pp.15-21
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• 2017

Recently, users' interest in IoT related products is increasing as the 4th industrial revolution has become social. The types and functions of sensors used in IoT devices are becoming increasingly diverse, and mutual authentication technology of IoT devices is required. In this paper, we propose an efficient double signature authentication scheme using Pascal's triangle theory so that different types of IoT devices can operate smoothly with each other. The proposed scheme divides the authentication path between IoT devices into two (main path and auxiliary path) to guarantee authentication and integrity of the IoT device. In addition, the proposed scheme is suitable for IoT devices that require a small capacity because they generate keys so that additional encryption algorithms are unnecessary when authenticating IoT devices. As a result of the performance evaluation, the delay time of the IoT device is improved by 6.9% and the overhead is 11.1% lower than that of the existing technique. The throughput of IoT devices was improved by an average of 12.5% over the existing techniques.

• Convergence Security Journal
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• v.19 no.3
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• pp.71-79
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• 2019

The demand of smart cars is increasing rapidly. International stand organize such as 3GPP and 5GAA are proposing standard communication protocvols for connected-car, and automotive network infrastructure. But Smart car network have many security threats and more dangerous against the existed wire communication network. Typically, peripheral devices of a smart car may disguise their identity and steal location information and personal information about the vehicle. In addition, the infrastructure elements around smart cars can conspire and put driving cars in danger, threatening lives. This is a very serious security threat. Therefore, in order to solve these problems, we proposed a system that is secure from collusion and tampering attacks using attribute-based authorize delegation method and threshold encryption algorithms. We have demonstrated using a semantic safety model that the proposed system can be safe from collusion attack.

• Journal of Convergence for Information Technology
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• v.11 no.11
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• pp.66-74
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• 2021

With the development of the Internet, user authentication technology that proves me online is improving. Existing ID methods pose a threat of personal information leakage if the service provider manages personal information and security is weak, and the information subject is to the service provider. In this study, as online identification technology develops, we propose a DID-based self-authentication model to prevent the threat of leakage of personal information from a centralized format and strengthen sovereignty. The proposed model allows users to directly manage personal information and strengthen their sovereignty over information topics through VC issued by the issuing agency. As a research method, a self-authentication model that guarantees security and integrity is presented using a decentralized identifier method based on distributed ledger technology, and the security of the attack method is analyzed. Because it authenticates through DID Auth using public key encryption algorithms, it is safe from sniffing, man in the middle attack, and the proposed model can replace real identity card.

• Convergence Security Journal
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• v.18 no.4
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• pp.27-33
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• 2018

Stream cipher is an one-time-pad type encryption algorithm that encrypt plaintext using simple operation such as XOR with random stream of bits (or characters) as symmetric key and its security depends on the randomness of used stream. Therefore we can design more secure stream cipher algorithm by using mathematical analysis of the stream such as period, linear complexity, non-linearity, correlation-immunity, etc. The key stream in stream cipher is generated in linear feedback shift register(LFSR) having characteristic polynomial. The primitive polynomial is the characteristic polynomial which has the best security property. It is used widely not only in stream cipher but also in SEED, a block cipher using 8-degree primitive polynomial, and in Chor-Rivest(CR) cipher, a public-key cryptosystem using 24-degree primitive polynomial. In this paper we present the concept and various properties of primitive polynomials in Galois field and prove the theorem finding the number of irreducible polynomials and primitive polynomials over $F_p$ when p is larger than 2. This kind of research can be the foundation of finding primitive polynomials of higher security and developing new cipher algorithms using them.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.5
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• pp.37-47
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• 2004

The security of personal informations has been an important issue since the field of smart card applications has been expanded explosively. The security of smart card is based on cryptographic algorithms, which are highly required to be implemented into hardware for higher speed and stronger security. In this paper, a SEED cryptographic processor is designed by employing one round key generation block which generates 16 round keys without key registers and one round function block which is used iteratively. Both the round key generation block and the F function are using only one G function block with one 5${\times}$l MUX sequentially instead of 5 G function blocks. The proposed SEED processor has been implemented such that each round operation is divided into seven sub-rounds and each sub-round is executed per clock. Functional simulation of the proposed cryptographic processor has been executed using the test vectors which are offered by Korea Information Security Agency. In addition, we have evaluated the proposed SEED processor by executing VHDL synthesis and FPGA board test. The die area of the proposed SEED processor decreases up to approximately 40% compared with the conventional processor.