• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.9
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• pp.3907-3923
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• 2020

An enhanced irregular repetition slotted ALOHA (IRSA) protocol is proposed by using polarization characteristic of satellite link and MIMO detection in low earth orbit (LEO) satellite networks, which is dubbed polarized MIMO IRSA (PM-IRSA). In the proposed scheme, one or two packets in one slot can be decoded by employing polarized MIMO detection, and more than two collided packets in multiple slots which can construct the virtual MIMO model can be decoded by the MIMO detection algorithm. The performance of the proposed scheme is analyzed with the density evolution (DE) approach and the degree distribution is optimized to maximize the system throughput by using a differential evolution. Numerical results certify our analysis and show that the normalized throughput of the proposed PM-IRSA can achieve 1.89 bits/symbol.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.1
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• pp.74-96
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• 2023

At present, the smart grid has become one of the indispensable infrastructures in people's lives. As a commonly used communication method, wireless communication is gradually, being widely used in smart grid systems due to its convenient deployment and wide range of serious challenges to security. For the insecurity of the schemes based on large integer factorization and discrete logarithm problem in the quantum environment, an identity-based key management scheme for smart grid over lattice is proposed. To assure the communication security, through constructing intra-cluster and inter-cluster multi-hop routing secure mechanism. The time parameter and identity information are introduced in the relying phase. Through using the symmetric cryptography algorithm to encrypt improve communication efficiency. Through output the authentication information with probability, the protocol makes the private key of the certification body no relation with the distribution of authentication information. Theoretic studies and figures show that the efficiency of keys can be authenticated, so the number of attacks, including masquerade, reply and message manipulation attacks can be resisted. The new scheme can not only increase the security, but also decrease the communication energy consumption.

• Journal of the Korea Computer Industry Society
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• v.6 no.3
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• pp.465-476
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• 2005

The wireless sensor network consists of a number of sensor nodes which have physical constraints. Each sensor node senses surrounding environments and sends the sensed information to Sink. In order to alleviate the inherent vulnerability in security of the wireless sensor nodes with the hardware constraints, the lightweight security protocol is needed and a variety of research is ongoing. In this paper, we propose a non-hierarchical sensor network and a security protocol that is suitable for monitoring man-made objects such as bridges. This paper, furthermore, explores a two-layer authentication, key distribution scheme which distributes the key and location of a sensor node in advance, and an effective security routing protocol which can take advantage of the Sleep and Awake state. This also results in the increased data transfer rate by increasing the number of alternative routing paths and the reduced energy consumption rate.

• The Journal of the Korea Contents Association
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• v.3 no.3
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• pp.40-46
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• 2003

In the paper, designed digital contents security module to check unlawfulness reproduction and distribution of digital contents. This paper applied Diffie-Hellman algorithm that use discrete logarithm and random number as primary for public key application to create encryption key that agree each other through communication channel between DCPS and HOST, and applied Triple DES repeat DES 3 times through 2 different encryption key that is selecting ANSI X9.17 that is key management standard, ISO 8732 and PEM(Privacy-Enhanced Mail) etc. by secondary protection for safe transmission of digital contents in transmission line. Designed security module consist of key exchange module, key derivation module and copy protection processing module. Digital contents security module that design in this thesis checks reproduction and distribution of digital contents by unauthenticated user through user certification function and digital contents encryption function, and protect digital contents transmission line.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.5
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• pp.2469-2490
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• 2019

A low-energy adaptive clustering hierarchy (LEACH) protocol is a low-power adaptive cluster routing protocol which was proposed by MIT's Chandrakasan for sensor networks. In the LEACH protocol, the selection mode of cluster-head nodes is a random selection of cycles, which may result in uneven distribution of nodal energy and reduce the lifetime of the entire network. Hence, we propose a new selection method to enhance the lifetime of network, in this selection function, the energy consumed between nodes in the clusters and the power consumed by the transfer between the cluster head and the base station are considered at the same time. Meanwhile, the improved FTBA algorithm integrating the curve strategy is proposed to enhance local and global search capabilities. Then we combine the improved BA with LEACH, and use the intelligent algorithm to select the cluster head. Experiment results show that the improved BA has stronger optimization ability than other optimization algorithms, which the method we proposed (FTBA-TC-LEACH) is superior than the LEACH and LEACH with standard BA (SBA-LEACH). The FTBA-TC-LEACH can obviously reduce network energy consumption and enhance the lifetime of wireless sensor networks (WSNs).

• Journal of Digital Convergence
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• v.11 no.12
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• pp.423-430
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• 2013

With the active Internet e-commerce and the financial sector, mutual authentication between users and service providers has become very important. Because ID- and password-based authentication is of low security, one-time password authentication methods are widely used. The existing one-time password authentication scheme of S/Key authentication method is fraught with a number of issues in addition to plain text transmission, and the method of Kim Gong-ki et al. does not offer suggestions for session key generation and distribution method. Proposed in this paper is a protocol that solves these problems.

• International Journal of Contents
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• v.8 no.3
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• pp.79-82
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• 2012

In digital contents distribution environments, a user authentication is an important security primitive to allow only authenticated user to use right services by checking the validity of membership. For example, in Internet Protocol Television (IPTV) environments, it is required to provide an access control according to the policy of content provider. Remote user authentication and key agreement scheme is used to validate the contents accessibility of a user. We propose a novel user authentication scheme using smart cards providing a secure access to multimedia contents service. Each user is authenticated using a subset of attributes which are issued in the registration phase without revealing individual's identity. Our scheme provides the anonymous authentication and the various permissions according to the combination of attributes which are assigned to each user. In spite of more functionality, the result of performance analysis shows that the computation and communication cost is very low. Using this scheme, the security of contents distribution environments in the client-server model can be significantly improved.

• Journal of Korea Multimedia Society
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• v.17 no.7
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• pp.778-786
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• 2014

Buyer-seller watermarking protocol is one of the copyright protection techniques which combine a cryptographic protocol used in electronic commerce with a digital wetermarking scheme aiming at proving the ownership of multimedia contents and preventing the illegal reproduction and redistribution of digital contents. In this paper, it is proposed a new watermarking scheme in an encrypted domain in an image that is based on the block-DCT framework. In order to implement watermarking scheme in a public-key cryptosystem, it is divided that frequency coefficients exist as real number into integer and decimal layer. And the decimal layer is modified integer type through integral-processing. Also, for robustness and invisibility required in watermarking scheme, it is designed a direction-adaptive watermarking scheme based on locally edge-properties of each block in an image through analyzing distribution property of the frequency coefficients in a block using JND threshold.

• The Transactions of the Korea Information Processing Society
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• v.6 no.1
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• pp.107-114
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• 1999

Recently as services in ATM are diversified, the need for security has been increased, But when we added the security features in ATM, the Compatibility and transparency with existing systems must be considered after analyzing threats of security. This paper designs the security protocol in ATM protocol stack and defines the primitivies and processing procedure of messages which are need in the security layer. Also, this paper presents the authentication and key distribution procedure which can be adopted at call establishment. The presented authentication protocol can be used for point-to-point method as well as point-to-multipoint method. and the correctness of this protocol is verified using GNY logic.

• Journal of Electrical Engineering and Technology
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• v.6 no.5
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• pp.605-612
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• 2011

As the power grids are integrated into one big umbrella called a "smart grid," communication protocol plays a key role in successful operations. The successful deployment of smart grid interoperability is a major hurdle that must be overcome. The micro grid, a small power system that distributes energy resource, is operated in diverse regions. Different vendors use different communication protocols in the operation of the micro grid. Recently, the IEC 61850 has been legislated to solve the interoperability problems in power utility automation. The present paper presents a micro grid system based on the IEC 61850 protocol. It consists of a micro grid monitoring system, a protocol converter that transforms serial data to IEC 61850 data, and distributed energy resource controllers for diverse DER nodes. A developed communication gateway can be deployed for DER controllers with serial links to exchange data with IEC 61850-based devices. The gateway can be extended to IEC 61850-based distribution automation systems, substation automation systems, or SCADA.