• Journal of Information Processing Systems
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• v.14 no.1
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• pp.6-31
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• 2018

With the rapid development of the science and technology, it has been becoming more and more convenient to obtain abundant information via the diverse multimedia medium. However, the contents of the multimedia are easily altered with different editing software, and the authenticity and the integrity of multimedia content are under threat. Forensics technology is developed to solve this problem. We focus on reviewing the blind image forensics technologies for copy-move forgery in this survey. Copy-move forgery is one of the most common manners to manipulate images that usually obscure the objects by flat regions or append the objects within the same image. In this paper, two classical models of copy-move forgery are reviewed, and two frameworks of copy-move forgery detection (CMFD) methods are summarized. Then, massive CMFD methods are mainly divided into two types to retrospect the development process of CMFD technologies, including block-based and keypoint-based. Besides, the performance evaluation criterions and the datasets created for evaluating the performance of CMFD methods are also collected in this review. At last, future research directions and conclusions are given to provide beneficial advice for researchers in this field.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.7
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• pp.1469-1474
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• 2004

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.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.9
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• pp.4567-4587
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• 2017

With the growth of the Internet and the extensive applications of image editing software, it has become easier to manipulate digital images without leaving obvious traces. Copy-move is one of the most common techniques for image forgery. Image blind forensics is an effective technique for detecting tampered images. This paper proposes an improved copy-move forgery detection method based on the discrete cosine transform (DCT). The quantized DCT coefficients, which are feature representations of image blocks, are truncated using a truncation factor to reduce the feature dimensions. A method for judging whether two image blocks are similar is proposed to improve the accuracy of similarity judgments. The main transfer vectors whose frequencies exceed a threshold are found to locate the copied and pasted regions in forged images. Several experiments are conducted to test the practicability of the proposed algorithm using images from copy-move databases and to evaluate its robustness against post-processing methods such as additive white Gaussian noise (AWGN), Gaussian blurring, and JPEG compression. The results of experiments show that the proposed scheme effectively detects both copied region and pasted region of forged images and that it is robust to the post-processing methods mentioned above.

• 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.

• Journal of the Korea Society of Computer and Information
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• v.24 no.4
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• pp.65-71
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• 2019

IAs smart device penetration rate is more than 90%, mobile transaction ratio using smart device is increasing. Smart contracts are used in various areas of real life including smart trading. By applying smart contracts to the platform for smart transactions through block-chain technology, the threat of hacking or forgery can be reduced. However, various threats to devices in smart transactions can pose a threat to the use of block chain Etherium, an important element in privilege and personal information management. Smart contract used in block chain Ethereum includes important information or transaction details of users. Therefore, in case of an attack of privilege elevation, it is very likely to exploit transaction details or forge or tamper with personal information inquiry. In this paper, we propose a detection and countermeasure method for privilege escalation attack, which is especially important for block chain for secure smart transaction using block chain Ethereum. When comparing the results of this study with the results of similar applications and researches, we showed about 12~13% improvement in performance and suggested the future countermeasures through packet analysis.

• International Journal of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.169-175
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• 2024

In this paper, we introduce a novel approach to enhance document security by integrating Computer Generated Hologram(CGH) encryption technology with a system for document encryption, printing, and subsequent verification using a smartphone application. The proposed system enables the encryption of documents using CGH technology and their printing on the edges of the document, simplifying document verification and validation through a smartphone application. Furthermore, the system leverages high-resolution smartphone cameras to perform online verification of the original document and supports offline document decryption, ensuring tamper detection even in environments without internet connectivity. This research contributes to the development of a comprehensive and versatile solution for document security and integrity, with applications in various domains.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.4
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• pp.661-674
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• 2021

Malware, such as a rootkit that modifies the kernel, can adversely affect the analyst's judgment, making the analysis difficult or impossible if a mechanism to evade memory analysis is added. Therefore, we plan to preemptively respond to malware such as rootkits that bypass detection through advanced kernel modulation in the future. To this end, the main structure used in the Windows kernel was analyzed from the attacker's point of view, and a method capable of modulating the kernel object was applied to modulate the memory dump file. The result of tampering is confirmed through experimentation that it cannot be detected by memory analysis tool widely used worldwide. Then, from the analyst's point of view, using the concept of tamper resistance, it is made in the form of software that can detect tampering and shows that it is possible to detect areas that are not detected by existing memory analysis tools. Through this study, it is judged that it is meaningful in that it preemptively attempted to modulate the kernel area and derived insights to enable precise analysis. However, there is a limitation in that the necessary detection rules need to be manually created in software implementation for precise analysis.

• Journal of Information Processing Systems
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• v.14 no.3
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• pp.666-679
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• 2018

The discrete wavelet transform (DWT) has good multi-resolution decomposition characteristic and its low frequency component contains the basic information of an image. Based on this, a fragile watermarking using the local binary pattern (LBP) and DWT is proposed for image authentication. In this method, the LBP pattern of low frequency wavelet coefficients is adopted as a feature watermark, and it is inserted into the least significant bit (LSB) of the maximum pixel value in each block of host image. To guarantee the safety of the proposed algorithm, the logistic map is applied to encrypt the watermark. In addition, the locations of the maximum pixel values are stored in advance, which will be used to extract watermark on the receiving side. Due to the use of DWT, the watermarked image generated by the proposed scheme has high visual quality. Compared with other state-of-the-art watermarking methods, experimental results manifest that the proposed algorithm not only has lower watermark payloads, but also achieves good performance in tamper identification and localization for various attacks.