• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.6
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• pp.159-166
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• 2013

Recently, because the interest and needs in privacy protection are growing, smartcard-based remote user authentication schemes have been actively studied to provide the user anonymity. In 2008, Kim et al. first proposed an authentication scheme in order to ensure the user anonymity against both external attackers and the remote server and track malicious users with the help of a trusted trace sever. However, in 2010, Lee et al. showed that Kim et al.'s scheme cannot provide the user anonymity against remote server, which is because the server can trace users without any help of the trace server, and then proposed a improved scheme. On the other hand, in 2010, Horng et al. proposed an authentication scheme with non-tamper resistant smart cards, in which the non-tamper resistant smart card means that an attacker may find out secret information stored in the smart card through special data analysis techniques such as monitoring power consumption, to be secure against a variety of attacks and to provide the user anonymity against external attackers. In this paper, we will propose a remote user authentication scheme with non-tamper resistant smart cards not only to ensure the user anonymity against both external attackers and the remote server but also to track malicious users with only the help of a trusted trace sever.

• The Journal of Information Technology
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• v.2 no.2
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• pp.177-197
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• 1999

On regarding Problems on information security technology that have its rise in the Introduction of electronic money lately, security evaluation of the types of electronic money is important. Therefore in this paper I tried to analyse introduction viladity based on that,in korea. In perticular, there is a synthetical and systematical study on the security of eletronic money, on the viewpoint of choice combination of cryptography technology and the types of attacks on it. And in case of the electronic money that the criterion of efficiency and functionism is superior to that of security, I emphasize on the fact that it could be valid electronic money if it were supplemented by tamper resistance technology in middle-long term

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.12
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• pp.4588-4603
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• 2014

In this paper, we present a high-quality image authentication scheme based on absolute moment block truncation coding. In the proposed scheme, we use the parity of the bitmap (BM) to generate the authentication code for each compressed image block. Data hiding is used to authenticate whether the content has been altered or not. For image authentication, we embed the authentication code to quantization levels of each image block compressed by absolute moment block truncation coding (AMBTC) which will be altered when the host image is manipulated. The embedding position is generated by a pseudo-random number generator for security concerned. Besides, to improve the detection ability we use a hierarchical structure to ensure the accuracy of tamper localization. A watermarked image can be precisely inspected whether it has been tampered intentionally or incautiously by checking the extracted watermark. Experimental results demonstrated that the proposed scheme achieved high-quality embedded images and good detection accuracy, with stable performance and high expansibility. Performance comparisons with other block-based data hiding schemes are provided to demonstrate the superiority of the proposed scheme.

• Journal of Ubiquitous Convergence Technology
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• v.2 no.1
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• pp.18-26
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• 2008

The invariance relation existing in the non-negative matrix factorization (NMF) is used for constructing robust image hashes in this work. The image is first re-scaled to a fixed size. Low-pass filtering is performed on the luminance component of the re-sized image to produce a normalized matrix. Entries in the normalized matrix are pseudo-randomly re-arranged under the control of a secret key to generate a secondary image. Non-negative matrix factorization is then performed on the secondary image. As the relation between most pairs of adjacent entries in the NMF's coefficient matrix is basically invariant to ordinary image processing, a coarse quantization scheme is devised to compress the extracted features contained in the coefficient matrix. The obtained binary elements are used to form the image hash after being scrambled based on another key. Similarity between hashes is measured by the Hamming distance. Experimental results show that the proposed scheme is robust against perceptually acceptable modifications to the image such as Gaussian filtering, moderate noise contamination, JPEG compression, re-scaling, and watermark embedding. Hashes of different images have very low collision probability. Tampering to local image areas can be detected by comparing the Hamming distance with a predetermined threshold, indicating the usefulness of the technique in digital forensics.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.4
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• pp.579-586
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• 2017

The defense industry has become a global industry, and military technology is actively being traded between countries to increase their military capabilities. The Republic of Korea has been ranked one of the top 10 countries for exports of military technology. To maintain competitive advantages in the global defense industry, it is essential to protect key technologies employed by exported weapon systems. Various techniques have been developed for protection of confidential technologies in weapon systems, and the U.S. DoD has been leading the development of the protection techniques. This paper reviews current anti-tampering techniques that prevent leakage of key technology from weapon exportation or pillage. Based on the protection techniques employed by the U.S. DoD Anti-Tamper Executive Agent, this paper suggests novel design methods for protection of confidential technologies. The proposed design methods were tested on an actual weapon system.

• Journal of Korea Multimedia Society
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• v.12 no.8
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• pp.1120-1127
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• 2009

The commensurate number of the attacks and infringement targeting a vulnerability of the game service has been increasing constantly, due to the dramatic growth and expansion of the impact of the game industry. However, there exist no subsequent researches for the differentiated technology, which is to prevent the reverse function of the game service. Therefore, in this study, we examined the current status of infringement toward online game services which are provided in the market currently and designed the proper technical measures for a manipulation of the game service which is the most vulnerable part. We have encrypted an execution file and decrypted it in real time process. Furthermore, we conducted debugging, disassemble, and prevented a its own memory dump, also concealed the information to overcome the module dependency to preclude a manipulation.

• Magazine of the Korean Society of Agricultural Engineers
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• v.28 no.4
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• pp.66-76
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• 1986

This study was attempted to investigate the effects of delayed compaction on the unconfined compressive strengh and dry density of Soil-cement mixtures. Soil-cement construction is a time-consuming procedure. Time-delay is known as a detrimental factor to lower the quality of soil-cement layer. A laboratory test was performed using coarse and fine weathered granite soils. The soils were mixed with 7% cement at optimum moisture content and excess moisture content in part. Socondary additives such as lime, gypsum-plaster, flyash and sugar were tried to counteract the detri-mental effect of delayed compaction. The specimens were compacted by Harvard Miniature Compaction Apparatus at 0,1,2,4,6 hors after mixing. Two kinds of compactive efforts(9 kgf and 18 kgf tamper) were applied. The results were summarized as follows: 1.With the increase of time delay, the decrease rate of dry density of the specimen compacted by 9 kgf tamper was steeper than that of the specimen compacted by 18kgf tamper. In the same manner, soil-B had steeper decreasing rate of dry density than soil-A. 2.Based on the results of delayed compaction tests, the dry density and unconfined compressive sterngth were rapidly decreased in the early 2 hours delay, while those were slowly decreased during the time delay of 2 to 6 hours. 3.The dry density and unconfined compressive strength were increased by addition of 3% excess water to the optimum moisture content during the time delay of 2 to 6 hours. 4.Without time delay in compaction, the dry densities of soil-A were increased by adding secondary additives such as lime, gypsum-plaster, flyash and sugar, on the other hand, those of soil-B were decreased except for the case of sugar. 5.The use of secondary additives like lime, gypsum-plaster, flyash and sugar could reduce the decrease of unconfined compressive strength due to delayed compaction. Among them, lime was the most effective. 6.From the above mentioned results, several recommendations could be suggested in order to compensate for losses of unconfined compressive strenght and densit v due to delayed compaction. They are a) to use coarse-grained granite soil rather than fined-grained one, b) to add about 3% excess compaction moisture content, c) to increase compactive effort to a certain degree, and d) to use secondary additives like line gypsum-plaster, flyash, and sugar in proper quantity depending on the soil types.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.623-626
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• 2002

Extreme development in digital multimedia has raised anxiety in the minds of copyrighted content owners. This has resulted in the creation of several watermarking techniques. This paper, proposes a method of embedding a perceptually transparent digital signal, named semi-fragile watermark in the wavelet domain, utilizing the characteristics of the human visual system. So as to detect attacks inflicted on the content and use an algorithm to specify the character of the attack.

• Proceedings of the KSR Conference
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• 2000.11a
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• pp.450-457
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• 2000

This paper establishes a scheme to estimate track quality using standard deviation and deterioration rate of track irregularities. To provide index of quality, standard deviation and deterioration rate of track irregularities are analyed. As an index, standard deviation and deterioration rate were applied to decision of corrective maintenance and replacement maintenance, respectively. Further, this paper proposes a basic scheme for a modernization of mechanize track maintenance that using MTT(Multiple Tie Tamper) and Ballast Cleaner.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.1113-1118
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• 2004

Ballasted track is constructed in consideration of the maintenance. The application time and frequency of MTT(Multiple Tie Tamper) and BS(Ballast Cleaner) depend on track geometry measurements. This paper presents the application of Ground Penetrating Radar(GPR), Falling Weight Deflectometer(FWD), and Portable Ballast Sampler (PBS) to evaluate the effects of track geometry due to substructure deterioration and to build a reliable substructure evaluation system.