• 전기학회논문지
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• 제65권12호
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• pp.2153-2158
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• 2016

Multimedia such as image, audio, and video is easy to create and distribute with the advance of IT. Since novice uses them for illegal purposes, multimedia forensics are required to protect contents and block illegal usage. This paper presents a multimedia forensic algorithm for video to identify the device used for acquiring unknown video files. First, the way to calculate a sensor pattern noise using Wiener filter (W-SPN) is presented, which comes from the imperfection of photon detectors against light. Then, the way to identify the device is explained after estimating W-SPNs from the reference device and the unknown video. For the experiment, 30 devices including DSLR, compact camera, smartphone, and camcorder are tested and analyzed quantitatively. Based on the results, the presented algorithm can achieve the 96.0% identification accuracy.

• Journal of Information Processing Systems
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• 제14권1호
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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.

• 한국멀티미디어학회논문지
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• 제10권3호
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• pp.365-372
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• 2007

세계에서 생성되는 정보의 대부분은 디지털 데이터로 만들어지고 있다. 이러한 디지털 저작물들은 불법 사용이 손쉽기 때문에 법적인 보호 장치나 기법이 꼭 필요하다. 그래서 지금까지 많은 연구가들은 다양한 기법들을 개발하고 있다. 지금까지 대부분의 기법들은 디지털 저작물 침해에 관한 법적인 증거 자료 확보를 위해 디스크 검증과 같은 물리적 또는 화학적인 방법 개발에 초점을 두고 있다. 본 논문에서는 사용자가 부적당하게 저작물을 사용할 때 이를 인지하고 법적 위배 사항을 통지해 주도록 하는 컴퓨터 포렌식 기반 디지털 저작물 보호 시스템을 개발하였다. 또한 계속적으로 침해 사실이 진행된다면 이런 일련의 위배 행위를 지적재산권법 매핑에 의하여 법적 증거 자료로 사용할 수 있도록 시스템에 저장하도록 한다. 이 기법은 디지털 증거 조작이나 증거 인멸의 문제로부터 데이터를 보호할 수 있다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권8호
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• pp.3943-3957
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• 2016

As digital evidence has a highly influential role in proving the innocence of suspects, methods for integrity verification of such digital evidence have become essential in the digital forensic field. Most surveillance camera systems are not equipped with proper built-in integrity protection functions. Because digital forgery techniques are becoming increasingly sophisticated, manually determining whether digital content has been falsified is becoming extremely difficult for investigators. Hence, systematic approaches to forensic integrity verification are essential for ascertaining truth or falsehood. We propose an integrity determination method that utilizes the structure of the video content in a Video Event Data Recorder (VEDR). The proposed method identifies the difference in frame index fields between a forged file and an original file. Experiments conducted using real VEDRs in the market and video files forged by a video editing tool demonstrate that the proposed integrity verification scheme can detect broken integrity in video content.

• Journal of Information Processing Systems
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• 제18권3호
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• pp.402-410
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• 2022

Digital data can be manipulated easily, so information related to the timestamp is important in establishing the reliability of the data. The time values for a certain file can be extracted following the analysis of the filesystem metadata or file internals, and the information can be utilized to organize a timeline for a digital investigation. Suppose the reversal of a timestamp is found on a mobile device during this process. In this case, a more detailed analysis is required due to the possibility of anti-forensic activity, but little previous research has investigated the handling and possible manipulation of timestamps on mobile devices. Therefore, in this study, we determine how time values for multimedia files are handled according to the operating system or filesystem on mobile devices. We also discuss five types of timestamps-file created (C), last modified (M), last accessed (A), digitalized (Di), and filename (FN) of multimedia files, and experimented with their operational features across multiple devices such as smartphones and cameras.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.377-378
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• 2006

The proposed method measures the correlation maps of SVD that are used to interpret data relations and structures between the original image and the distorted image. It seems that the SVD results can be used to assist us in gaining information about covariance structure of two images. This method is able to work in the complete absence of any digital watermark or signature. The effectiveness of this method is seen through testing the robustness against JPEG compression.

• 한국멀티미디어학회논문지
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• 제19권1호
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• pp.30-40
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• 2016

Recently, the competition among global IT companies for the market occupancy of the IoT(Internet of Things) is fierce. Internet of Things are all the things and people around the world connected to the Internet, and it is becoming more and more intelligent. In addition, for the purpose of providing users with a customized services to variety of context-awareness, IoT platform and related research have been active area. In this paper, we analyze third party instant messengers of Windows 8 Style UI and propose a digital forensic methodology. And, we are well aware of the Android-based map and navigation applications. What we want to show is GPS information analysis by using the R. In addition, we propose a structured data analysis applying the hierarchical clustering model using GPS data in the digital forensics modules. The proposed model is expected to help support the IOT services and efficient criminal investigation process.

• 한국멀티미디어학회:학술대회논문집
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• 한국멀티미디어학회 2012년도 춘계학술발표대회논문집
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• pp.231-233
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• 2012

컴퓨터 및 프린터 기술의 발전으로 디지털 문서 활용 사례가 전 분야에 확산되면서 디지털 문서의 위 변조 범죄가 증가하고 많은 사회적인 문제를 야기하고 있다. 이러한 컴퓨터를 이용한 범죄의 증거를 수집하고 분석하기 위해 디지털 포렌식 기술의 발전이 더욱 중요해지고 있다. 디지털 포렌식은 PC나 휴대폰 등 각종 디지털 매체 등에 남아 있는 디지털 정보들을 수집 분석해 범죄 단서를 찾는 컴퓨터 법의학이다. 본 논문에서는 프린터기로 출력된 문서의 고해상도 영상현미경 이미지를 사용하여 원본 여부를 판별 할 수 있는 프린터기 동일 여부 판별 기술을 제안한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권12호
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• pp.5087-5102
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• 2015

Rapid popularization of smart cell phone equipped with camera has led to a number of new legal and criminal problems related to multimedia such as digital image, which makes cell phone source identification an important branch of digital image forensics. This paper proposes a classifier combination based source identification strategy for cell phone images. To identify the outlier cell phone models of the training sets in multi-class classifier, a one-class classifier is orderly used in the framework. Feature vectors including color filter array (CFA) interpolation coefficients estimation and multi-feature fusion is employed to verify the effectiveness of the classifier combination strategy. Experimental results demonstrate that for different feature sets, our method presents high accuracy of source identification both for the cell phone in the training sets and the outliers.

• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제6권1호
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• pp.15-22
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• 2017

인터넷 기술이 급속도로 발전함에 따라서 다양한 소셜 네트워크 서비스들이 나타나고 있다. 특히 스마트 기기들이 발전함에 따라서 소셜 네트워크 상에는 멀티미디어 콘텐츠가 넘쳐나고 있다. 그러나 불법적 목적을 가진 사용자에 의해 발생하는 범죄도 증가하면서 멀티미디어 포렌식을 이용한 콘텐츠 보호 및 불법 사용 차단의 필요성이 사회적으로 대두되고 있다. 본 논문에서는 멀티미디어 포렌식 기술의 하나로 디지털 동영상 획득 장치 판별을 위한 포렌식 기술을 제안한다. 먼저 모폴로지 필터링을 이용한 센서 패턴 노이즈 추출하는 방법을 제안한다. 이를 이용하여 참조 장치에서 촬영한 참조 동영상의 센서 패턴 노이즈를 추정하고, 검사 동영상에서 센서 패턴 노이즈를 추출한다. 그리고 두 센서 패턴 노이즈 사이의 유사성 계산을 통하여 검사 동영상이 참조 장치로 촬영을 했는지 판별을 수행한다. 제안한 기술의 성능 분석을 위하여 DSLR 카메라, 콤팩트 카메라, 캠코더, 액션캠 및 스마트폰 등을 포함한 총 30대의 장치에 대하여 개발한 알고리즘에 대한 정량적 성능 분석을 수행하였고, 그 결과 96%의 판별 정확도를 달성하였다.