• Journal of Korea Multimedia Society
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• v.11 no.5
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• pp.588-596
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• 2008

For the patients' privacy, secure access control of medical images is essentially necessary. In this paper, two types of Region of Interest (ROI)-based selective encryption schemes are proposed, which concentrate on the security of crucial parts in medical images. The first scheme randomly inverts the most significant bits of ROI coefficients in several high frequency subbands in the transform domain, which only incurs little loss on compression efficiency. The second scheme employs a symmetric key encryption to encrypt selectively the ROI data in the final code-stream, which provides sufficient confidentiality. Both of two schemes are backward compatible so as to ensure a standard bitstream compliant decoder so the encrypted images can be reconstructed without any crash.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.6
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• pp.1117-1124
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• 2023

The security of information, including image content, is an essential part of today's communications technology and is critical to secure transmission. In this paper, a new ROI-based image encryption algorithm is proposed that can quickly encrypt images with a security level suitable for environments that require real-time data transmission for images containing sensitive information such as ID cards. The proposed algorithm is based on one dimensional 5-neighbor cellular automata, which can be implemented in hardware and performed hardware-friendly operations. Various experiments and analyses are performed to verify whether the proposed encryption algorithm is safe from various brute-force attacks.

• Journal of Korea Multimedia Society
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• v.8 no.11
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• pp.1462-1471
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• 2005

Recently, the medical image has been digitized by the development of computer science and digitization of the medical devices. There are needs for database service of the medical image and long term storage because of the construction of PACS(picture archiving and communication system) following DICOM(digital imaging communications in medicine) standards, telemedicine, and et al. However, it also caused some kinds of problems, such as illegal reproduction of medical image, proprietary rights and data authentication. In this paper, we propose the new digital watermarking technique for medical image based on public key encryption algorithm for integrity verification. It prevents illegal forgery that can be caused after transmitting medical image data remotely. The watermark is the value of bit-plane in wavelet transform of the original image for certification method of integrity verification. We proposed the embedding regions are randomly chosen considering ROI, and a digital signature is made using hash function of MD5 which input is a secret key. The experimental results show that the watermark embedded by the proposed algorithm can survive successfully in image processing operations and that the watermark's invisibility is good.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.2
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• pp.311-326
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• 2018

This paper has experimented using News sample video with QCIF ($176{\times}144$) resolution in JM v10.2 code of H.264/AVC-MPEG. The region of interest (ROI) to be encrypted occurred the drift by unnecessarily referring to each frame continuously in accordance with the characteristics of the motion prediction and compensation of the H.264 standard. In order to mitigate the drift, the latest related research method of re-inserting encrypted I-picture into a certain period leads to an increase in the amount of additional computation that becomes the factor increasing the bit-rate overhead of the entire video. Therefore, the reference search range of the block and the frame in the ROI to be encrypted is restricted in the motion prediction and compensation for each frame, and the reference search range in the non-ROI not to be encrypted is not restricted to maintain the normal encoding efficiency. In this way, after encoding the video with restricted reference search range, this article proposes a method of RC4 bit-stream encryption for the ROI such as the face to be able to identify in order to protect personal information in the video. Also, it is compared and analyzed the experimental results after implementing the unencrypted original video, the latest related research method, and the proposed method in the condition of the same environment. In contrast to the latest related research method, the bit-rate overhead of the proposed method is 2.35% higher than that of the original video and 14.93% lower than that of the latest related method, while mitigating temporal drift through the proposed method. These improved results have verified by experiments of this study.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.05a
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• pp.142-144
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• 2023

실생활에서 CCTV가 증가함에 따라 영상에서 개인정보 유출에 대한 관심도 증가하고 있다. CCTV로 녹화된 영상에서는 다양한 개인정보가 노출될 수 있기 때문에, 개인정보를 비식별화할 수 있는 영상 암호화 기술이 필요하다. 현재 다양한 영상녹화 장치에서 효율성을 위해 HEVC가 많이 사용되고 있으며, HEVC 영상에서 관심영역만을 암호화하는 실시간 관심영역 암호화 기술이 연구되고 있다. 기존의 HEVC 영상에서 관심영역 암호화 기법은 모든 프레임의 관심영역에 포함되는 타일을 암호화하므로 많은 연산자원을 필요로 한다. 본 논문에서는 선별된 일부 프레임에서 관심영역에 포함되는 타일을 선택적으로 암호화하여, 모든 프레임에서 관심영역의 비식별화를 유지하며 암호화 성능을 향상하는 방법을 제안한다. 결과적으로 제안한 방법을 사용함으로써 영상 암호화 시 전체 프레임에 대한 비식별화를 유지하면서 기존 방법보다 암호화에 걸리는 시간이 50.4% 감소하였다.