• Proceedings of the Korean Society of Computer Information Conference
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• 2017.07a
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• pp.121-122
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• 2017

컴퓨터의 주변 장치 중 하나인 마우스는 모니터의 2차원 평면에서 움직임을 인식하여 커서를 움직이는 입력 장치이며, 응용 프로그램을 편리하게 사용하고 다양한 편집을 가능하게 한다. 기존의 아이디/비밀번호 기반 인증 방법에서는 키보드 데이터가 노출되는 취약점이 존재하여 이미지 기반의 마우스 입력을 이용한 새로운 인증 방법이 등장하였지만, 이미지 기반 인증의 취약점 분석 및 실증에 대한 연구는 미비한 실정이다. 따라서 본 논문에서는 마이크로소프트 운영체제에서 제공하는 마우스 위치 추출 API인 GetCursorPos() 함수를 이용하여 마우스 데이터의 노출 가능성을 검증함으로써 취약점을 분석한다.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1412-1415
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• 2002

This paper describes a digital signature-based method for original and updated video authentication. The method uses multiple digital signatures in dealing with video data undergoing multiple change/updating. In addition, a feature based on neighbouring block similarity measure is applied to deal with certain image/video modification. The proposed method can cope with wide range of image/video tampering. It is suitable for practical use of video data, where updating may be performed by more than one legal parties. Experimental results are included with concluding remarks.

• Proceedings of the Korean Society of Computer Information Conference
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• 2018.01a
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• pp.177-178
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• 2018

키보드 정보가 노출되는 취약점이 발견되면서 키보드를 통하여 아이디 및 비밀번호를 입력하는 인증의 보안성 결여 문제가 대두되었다. 이를 대응하기 위하여 마우스를 통하여 비밀번호를 입력하는 이미지 기반 인증이 등장하였으며, 이 인증방식은 인터넷 뱅킹 및 결제 서비스와 같이 중요도가 높은 서비스에 도입되어 사용자가 입력하는 비밀번호를 안전하게 보호한다. 하지만 키보드와 동일하게 사용자가 입력하는 마우스 데이터가 노출되는 취약점이 발견되고 있으며, 본 논문에서는 WM_INPUT 메시지를 활용하여 노출되는 마우스 데이터를 보호하는 방안을 제시한다. 제시하는 방안은 WM_INPUT 메시지를 활용하는 공격을 효과적으로 방지하며, 이를 통하여 이미지 기반 인증방식의 안전성을 강화할 수 있을 것으로 사료된다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.01a
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• pp.115-116
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• 2022

비밀번호 인증 기술에서 키보드로부터 입력되는 데이터가 노출되는 문제점으로 인하여, 이미지 기반 인증 기술이 등장하였다. 이 기술은 주로 가상 키보드를 출력하고, 특정 위치에 클릭된 마우스 정보를 비밀번호로 활용한다. 마우스 데이터의 안전성 향상을 위하여 임의의 마우스 위치를 생성하는 랜덤 마우스 데이터 생성 기술이 등장하였지만, 해당 기술의 안전성 분석에 대한 연구가 미비한 실정이다. 따라서 본 논문에서는 GetCursorPos() 함수를 활용한 공격 기술과 WM_INPUT 메시지를 활용한 공격 기술을 기반으로 랜덤 마우스 데이터 생성 기술이 적용된 사이트에서의 마우스 데이터 취약점을 분석한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.7
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• pp.4516-4521
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• 2014

Digital watermarking for digital image authentication and integrity schemes are based on fragile watermarking and can detect any modifications in a watermark embedded image by comparing the embedded watermark with the regenerated watermark. Therefore, the digital watermark for image authentication and integrity should be erased easily when the image is changed by digital image processing, such as scaling or filtering etc. This paper proposes an effective tamper detection scheme for digital images. In the proposed scheme, the original image was divided into many non-overlapping $2{\times}2$ blocks. The digital watermark was divided into two LSB of each block and the image distortion was imperceptible to the human eye. The watermark extraction process can be used to determine if the watermarked image has been tampered. The experimental results successfully revealed the effectiveness of the proposed scheme.

• Journal of Software Assessment and Valuation
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• v.16 no.2
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• pp.143-151
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• 2020

The digital content's security and authentication are important in the field of digital content application. There are some methods to perform the authentication. The digital watermarking is one of authentication methods. Paper presents a digital watermark authentication method that works in the application of digital image. The proposed watermark has the triple status information and performs the embedding and the detection without original Content. When authenticating the owner information of digital content, an autocorrelation function is used. In addition, a spread spectrum method is used to be adaptive to the signal of the original content in the frequency domain(DWT Domain). Therefore, the possibility of errors occurring in the detection of hidden information was reduced. it also has a advantage what Watermarking in DWT has faster embedding and detection time than other transformation domains(DFT, DCT, etc.). if it has a an image of size N=mXm, the computational amount can be reduced from O(N·logN) to O(N). The particular advantage is that it can hide more information(bits) per bit.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.196-201
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• 2016

Digital watermarking is a technique used to hide information within digital media. Digital watermarking techniques can be classified as either robust watermarking or fragile watermarking. Robust watermarking techniques are generally used for the purpose of copyright protection. In addition, fragile watermarking techniques are used for the authentication and integrity verification of a digital image. Therefore, fragile watermarks should be easily breakable for trivial tampering of a watermarked image. This paper proposes an efficient fragile watermarking method for image tamper detection in the spatial domain. In the proposed method, a hash code and symmetric key encryption algorithm are used. The proposed method of inserting a watermark by dividing the original image into many blocks of small sizes is not weak against attacks, such as cut and paste. The proposed method can detect the manipulated parts of a watermarked image without testing the entire block of the image.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.4
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• pp.1499-1513
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• 2014

This paper proposes a novel blind image watermarking scheme exploiting Block Truncation Coding (BTC). Most of existing BTC-based watermarking or data hiding methods embed information in BTC compressed images by modifying the BTC encoding stage or BTC-compressed data, resulting in watermarked images with bad quality. Other than existing BTC-based watermarking schemes, our scheme does not really perform the BTC compression on images during the embedding process but uses the parity of BTC quantization data to guide the watermark embedding and extraction processes. In our scheme, we use a binary image as the original watermark. During the embedding process, the original cover image is first partitioned into non-overlapping $4{\times}4$ blocks. Then, BTC is performed on each block to obtain its BTC quantized high mean and low mean. According to the parity of high mean and the parity of low mean, two watermark bits are embedded in each block by modifying the pixel values in the block to make sure that the parity of high mean and the parity of low mean in the modified block are equal to the two watermark bits. During the extraction process, BTC is first performed on each block to obtain its high mean and low mean. By checking the parity of high mean and the parity of low mean, we can extract the two watermark bits in each block. The experimental results show that the proposed watermarking method is fragile to most image processing operations and various kinds of attacks while preserving the invisibility very well, thus the proposed scheme can be used for image authentication.

• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.901-904
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• 2000

A direct authentication from gray-scale image, instead of the conventional multi-step preprocessing, is proposed using Gabor filter-based features from the gray-scale fingerprint around core point. The core point is located as a reference point for the translation invariant matching. And its principal symmetry axis is detected for the rotation invariant matching from its neighboring region centered at the core point. And then fingerprint is divided into non-overlapping blocks with respect to the core point and features are directly extracted form the blocked gray level fingerprint using Gabor filter. The proposed fingerprint authentication is based on the Euclidean distance between the corresponding Gabor features of the input and the template fingerprints. Experiments are conducted on 300${\times}$300 fingerprints obtained from a CMOS sensor with 500 dpi resolution, and the proposed method could lower the False Reject Rate(FRR) to 18.2% under False Acceptance Rate(FAR) of 0%.

• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.721-724
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• 2000

This paper presents fingerprint authentication method based on minutiae quadrangle definded by neighboring two Delaunay triangles. In this method, we first make minutiae triangle through Delaunay triangulation which adaptively connect neighboring minutiae according to the local minutiae density distribution, and then use feature vectors in authentication which is extracted from the minutiae quadrangle formed by neighboring two minutiae triangles. This prevents the degradation of matching ratio caused by the errors in image processing or local deformation of the fingerprint, and we can authenticate more discriminately as this method reflects wider local area's topological features than the features extracted from the individual minutiae triangles. To evaluate the proposed algorithm's performance, experiment are conducted on 120 fingerprints, of which size is 256 ${\times}$ 364 with 500dpi resolution. Robust authentications are possible with low FRR.