• Journal of Korea Multimedia Society
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• v.19 no.2
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• pp.291-299
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• 2016

To enhance network efficiency, named-data networking (NDN) implements data caching functionality on intermediate network nodes, and then the nodes directly respond to request messages for cached data. Through the processing of request messages in intermediate node, NDN can efficiently reduce the amount of network traffic, also solve network congestion problems near data sources. Also, NDN provides a data authenticate mechanism so as to prevent various Internet accidents caused from the absence of an authentication mechanism. Hence, through applying NDN to various smart IT convergence services, it is expected to efficiently control the explosive growth of network traffic as well as to provide more secure services. Basically, it is important factors of NDN which data is cached and where nodes caching data is located in a network topology. This paper first analyzes previous works caching content based on the popularity of the content. Then ii investigates the hitting rate of caches in each node of a network topology, and then propose an improved caching scheme based on the result of the analyzation. Finally, it evaluates the performance of the proposal.

• Journal of Korea Multimedia Society
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• v.18 no.4
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• pp.483-491
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• 2015

Data hiding is one of protective methods that can authenticate the completeness of digital information and protect intelligent property rights and copyright through secret communications. In this paper, we propose a data hiding method using pixel-value modular operation that has a high capacity while maintaining a good visual quality. The proposed method can embed secret data on the every pixel of a cover image by modular operation. The experiment results demonstrate that the proposed method has a high capacity and good visual quality where the embedding capacity is 91,138 bytes, the PSNR is 47.94dB, and the Q index is 0.968.

• ETRI Journal
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• v.37 no.2
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• pp.338-347
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• 2015

The multi-carrier transmission signal in Multi-Carrier Code Division Multiple Access (MC-CDMA) has a high peak-to-average power ratio (PAPR), which results in nonlinear distortion and deteriorative system performance. An n-tuple selective mapping method is proposed to reduce the PAPR, in this paper. This method generates $2^n$ sequences of an original data sequence by adding n-tuple of n PAPR control bits to it followed by an interleaver and error-control code (ECC) to reduce its PAPR. The convolutional, Golay, and Hamming codes are used as ECCs in the proposed scheme. The proposed method uses different numbers of the n PAPR control bits to accomplish a noteworthy PAPR reduction and also avoids the need for a side-information transmission. The simulation results authenticate the effectiveness of the proposed method.

• Electronics and Telecommunications Trends
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• v.35 no.1
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• pp.25-33
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• 2020

Just as it is possible to distinguish people by using physical features, such as fingerprints, irises, veins, and faces, and behavioral features, such as voice, gait, keyboard input pattern, and signatures, the an IoT device includes various features that cannot be replicated. For example, there are differences in the physical structure of the chip, differences in computation time of the devices or circuits, differences in residual data when the SDRAM is turned on and off, and minute differences in sensor sensing results. Because of these differences, Sensor data can be collected and analyzed, based on these differences, to identify features that can classify the sensors and define them as sensor-based device DNA technology. As Similar to the biometrics, such as human fingerprints and irises, can be authenticatedused for authentication, sensor-based device DNA can be used to authenticate sensors and generate cryptographic keys that can be used for security.

• Proceedings of the IEEK Conference
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• 2004.06a
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• pp.297-300
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• 2004

In cellular communication, subscriber authentication is an essential technique. The mobile station should operate in conjunction with the base station to authenticate the identity. In CDMA system, authentication is the process by which information is exchanged between a mobile station and base station for the purpose of confirming the mobile station. A successful authentication process means that the mobile station and base station process identical sets of shared secret data(SSD). SSD can be generated by authentication algorithms. The cryptographic hash function is a practical way of authentication algorithms. In this paper, we propose and implement MD5 and SHA-1 with modified structure.

• Journal of the Korean Institute of Telematics and Electronics
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• v.21 no.3
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• pp.34-38
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• 1984

The master key on the multiuser MH public key cryptosystem, can be substituted for multiple private keys, is proposed and derived. Applying it to public key cryptosystem, it can be possible to save memory size by selecting the master key and easy to authenticate the truth of message and the identity of the sender. Vsing this master key, it is proved that the encryption time ratio of MH method is smaller than that of RSA's method.

• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.721-724
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• 2000

This paper presents fingerprint authentication method based on minutiae quadrangle definded by neighboring two Delaunay triangles. In this method, we first make minutiae triangle through Delaunay triangulation which adaptively connect neighboring minutiae according to the local minutiae density distribution, and then use feature vectors in authentication which is extracted from the minutiae quadrangle formed by neighboring two minutiae triangles. This prevents the degradation of matching ratio caused by the errors in image processing or local deformation of the fingerprint, and we can authenticate more discriminately as this method reflects wider local area's topological features than the features extracted from the individual minutiae triangles. To evaluate the proposed algorithm's performance, experiment are conducted on 120 fingerprints, of which size is 256 ${\times}$ 364 with 500dpi resolution. Robust authentications are possible with low FRR.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.407-410
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• 2003

We propose a new logo watermark scheme for digital images which embed a watermark by modifying middle-frequency sub-bands of wavelet transform. Independent component analysis (ICA) is introduced to authenticate and copyright protect multimedia products by extracting the watermark. To exploit the Human visual system (HVS) and the robustness, a perceptual model is applied with a stochastic approach based on noise visibility function (NVF) for adaptive watermarking algorithm. Experimental results demonstrated that the watermark is perfectly extracted by ICA technique with excellent invisibility, robust against various image and digital processing operators, and almost all compression algorithms such as Jpeg, jpeg 2000, SPIHT, EZW, and principal components analysis (PCA) based compression.

• Convergence Security Journal
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• v.4 no.2
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• pp.53-60
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• 2004

We describe CHAP authentication for roaming service method of visited ISP subscriber on GPRS network. We also illustrate how visited mobile ISP subscriber can access ISP server and authenticate RADIUS in home network via Gateway GPRS Support Node (GGSN) on GPRS/UMTS network for wireless internet service and roaming. For this we propose the modified CHAP message format, PCO Message format at MT, and interworking message and format between GGSN and RADIUS in home ISP network for wireless internet service of mobile ISP subscriber at GPRS network in this paper. We also show authentication results when visited mobile ISP subscriber via CHAP at GPRS network accesses the RADIUS server in home ISP network.

• Journal of Korea Society of Digital Industry and Information Management
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• v.5 no.1
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• pp.63-70
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• 2009

As individuals spend more time doing social and economic life on the web, the importance of protecting privacy against Phishing and Pharming attacks also increases. Until now, there have been researches on the methods of protection against Phishing and Pharming. However, these researches don't provide efficient methods for protecting privacy and don't consider Pharming attacks. In this paper, we propose an authentication protocol that protects user information from Phishing and Pharming attacks. In this protocol, the messages passed between clients and servers are secure because they authenticate each other using a hash function of password and location information which are certificated to clients and servers only. These messages are used only once, so that the protocol is secure from replay attacks and man-in-the-middle attacks. Furthermore, it is also secure from Pharming attacks.