• ETRI Journal
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• v.33 no.1
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• pp.60-70
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• 2011

Software is completely exposed to an attacker after it is distributed because reverse engineering is widely known. To protect software, techniques against reverse engineering are necessary. A code encryption scheme is one of the techniques. A code encryption scheme encrypts the binary executable code. Key management is the most important part of the code encryption scheme. However, previous schemes had problems with key management. In an effort to solve these problems in this paper, we survey the previous code encryption schemes and then propose a new code encryption scheme based on an indexed table. Our scheme provides secure and efficient key management for code encryption.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.479-488
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• 2005

Geopier soil reinforcement system which crushed aggregate is put into a hole and rammed the aggregate with tamper is a viable alternative to deep foundation to over-excavation and replacement. Also, Geopier is intermediate foundation of deep and shallow foundation. In this paper, the value of Geopier element stiffness modulus($K_g$) when designed is compared with the measured value($K_g$) by the in-situ modulus Load test in the field. Also, this paper presents a technology overview of system capabilities and application for foundation reinforcement of structures.

• Journal of Electrical Engineering and Technology
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• v.10 no.5
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• pp.2149-2154
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• 2015

This paper proposes a novel watermarking method to discover the tampers and localize it in digital image. The image which is to be used to generate a watermark is first wavelet decomposed and the edge feature from the sub bands of high frequency coefficients are retrieved to generate a watermark (Edge Feature Image) and which is to be embed on the cover image. Before embedding the watermark, the pixels of cover image are disordered through the Arnold Transform and this helps to upgrade the security of the watermark. The embedding of generated edge feature image is done only on the Least Significant Bit (LSB) of the cover image. The invisibleness and robustness of the proposed method is computed using Peak-Signal to Noise Ratio (PSNR) and Normalized Correlation (NC) and it proves that the proposed method delivers good results and the proposed method also detects and localizes the tampers efficiently. The invisibleness of proposed method is compared with the existing method and it proves that the proposed method is better.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.1 no.1
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• pp.29-34
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• 2008

A wavelet-based image watermarking scheme is proposed, based on the insertion of pseudo-random codes in the frequency domain. The original image is required for the watermark detection. The "strength" of the signature to be embedded depends on the image to be marked, thus fitting signal capacity. The experimental results prove that the method is more tamper resistant and less perceptible for any type of images than other well-known private methods in the frequency domains.

• Proceedings of the KIEE Conference
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• 2004.07d
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• pp.2574-2576
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• 2004

본 논문에서 디지털 영상의 인증과 무결성을 확인하는 새로운 워터마킹 기법을 제안하였다. 컨텐츠에 대한 인증과 무결성을 체크하는 방법 중, 암호학적 해쉬함수(MD5)를 이용한 Wong의 방법이 인증과 무결성을 위한 워터마크 방법으로는 가장 적합하다. 특히 이 방법은 암호학적인 해쉬함수를 사용하므로 워터마킹 알고리즘의 안정성이 암호학적 해쉬함수의 안정성에 의존하게 되므로 안전하다. 해쉬 값을 계산하려면 법(modulus), 보수 (complement), 시프트 (shift), XOR (bitwise exclusive-or) 등 연산이 필요하다. 그러나 본 논문에서는 곱셈 연산만 필요로 한 산술부호화기법 (Arithmetic coding)을 이용하였다. 이 기법은 입력되는 심벌 (symbol)들의 확률구간을 계속적으로 곱하여 결과적으로 얻어지는 누적확률구간을 출력한다. 본 논문에서 키(key) 값에 의하여 심벌들의 확률구간을 결정하고, 그리고 키 값에 의하여 심벌들의 입력순서론 재배치함으로써 결과적으로 얻어지는 누적확률 값은 키 값에 의존하게 하였다. 실험을 통하여 본 알고리즘이 무결성을 입증할 수 있고, PSNR은 51.13dB 이상으로서 아주 좋으며, 위변조를 판단하는데 소요되는 시간은 해쉬함수 (MD5)를 사용하는데 걸리는 시간이 1/3배이다. 그러므로 실시간으로 사용 가능하다.

• Proceedings of the KSR Conference
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• 2000.11a
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• pp.418-425
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• 2000

In this study, the evaluation for utilization of waste landfill was performed by field test to use waste landfill as construction site(Nangido in Seoul). The site where dynamic compaction test was carried out was divided by 4 yards. Yard 1, 2 were not eliminated widening of cover soil and Yard 3, 4 were eliminated it. Dynamic Compaction Pilot Test was carried out by the 15ton heavy tamper with drop height of 20m in Yard 1, 3 and with drop height of 15m in Yard 2, 4 We evaluated the compaction ability, optimum compaction number and noiseㆍvibration through field test, monitoring. To make use of waste landfill as a construction site, The dynamic compaction method is suitable for using in waste landfill as a construction site among the ground improvement methods.

• Journal of the Institute of Convergence Signal Processing
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• v.13 no.4
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• pp.187-193
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• 2012

An image authentication scheme for gray scale image through embedding a digital watermark by quantization of Integer Wavelet Transform (IWT) coefficients of the image is proposed in this paper. Proposed method is designed to detect modification of an image and to identify tampered location of the image. To embed the watermark mid-frequency band of a second level IWT was used. An approximation of the original image based on LL band was stored in LSB bits of the pixel data as a recovery mark for restoration of the image. Watermarked image has achieved a good PSNR of 40 dB compared to original cover image. Restored image quality was also very good with a PSNR of more than 35 dB compared to unmodified watermarked image even when 25% of the received image is cropped. Thus, the proposed method ensures a proper balance between the fidelity of the watermarked image and the quality of the restored image.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.12
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• pp.6175-6189
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• 2019

To slove the security and efficiency problem of anonymous authentication in vehicular ad-hoc network (VANET), we adopt the bilinear pairing theory to propose an identity-based batch anonymous authentication scheme for VANET. The tamper-proof device in the on-board unit and the trusted authority jointly realize the anonymity of vehicle identity and the signature of messages, which further enhances the security of this scheme, as well as reduces the overhead of trusted authority. Batch authentication can improve the efficiency of anonymous authentication for VANET. Security and efficiency analyses demonstrate that this scheme not only satisfies such security properties as anonymity, non-forgeability and non-repudiation, but also has advantage in time and space complexity. Simulation results show that this scheme can achieve good performance in real-time VANET communication.

• Information and Communications Magazine
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• v.32 no.6
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• pp.39-49
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• 2015

In cryptographic applications, the key protection is either knowledge-based (passwords) or possession-based (tamper-proof device). Unfortunately, both approaches are easily forgotten or stolen, thus introducing various key management issues. By incorporating biometrics technologies which utilize the uniqueness of personal characteristics, the security of cryptosystems could be strengthened as authentication now requires the presence of the user. Biometric Cryptosystem (BC) encompasses the design of cryptographic keys protection methods by incorporating biometrics. BC involves either key-biometrics binding or direct key generation from biometrics. However, the wide acceptance and deployment of BC solutions are constrained by the fuzziness related with biometric data. Hence, error correction codes (ECCs) should be adopted to ensure that fuzziness of biometric data can be alleviated. In this overview paper, we present such ECC solutions used in various BCs. We also delineate on the important facts to be considered when choosing appropriate ECCs for a particular biometric based solution from accuracy performance and security perspectives.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.268-273
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• 2008

The ballast, one of track components, plays an essential role as intermedium in transmitting train load to subgrade safely, and the deterioration of ballast directly effects the growth of track irregularity. So far, gravel fining of ballast track was mainly related to the repetition of train loads, but was gradually increased with using MTT(Multiple Tie Tamper) recently. Therefore, in this study, an evaluation of the abrasion and crush process of ballast particles was performed with outdoor field test by MTT works. From this study, the amount of abrasion and crush of ballast particles appeared to increase linearly with MTT works, and the gradient of particle size distribution curve appeared to deviate gradually from a criterion of aggregated ballast size distribution in high-speed railroad.