• Journal of Korea Multimedia Society
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• v.18 no.11
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• pp.1332-1341
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• 2015

This paper proposes a novel reversible secret sharing scheme using AES algorithm in encrypted images. In the proposed scheme, a role of the dealer is divided into an image provider and a data hider. The image provider encrypts the cover image with a shared secret key and sends it to the dealer. The dealer embeds the secret data into the encrypted image and transmits encrypted shadow images to the corresponding participants. We utilize Galois polynomial arithmetic operation over 2⁸ and the coefficient of the higher-order term is fixed to one in order to prevent the overflow. In experimental results, we demonstrate that the PSNR is sustained close to 44dB and the embedding capacity is 524,288 bits.

• Journal of Korea Multimedia Society
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• v.14 no.6
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• pp.759-765
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• 2011

In this paper, we proposed fast stream cipher MS64 for use mobile that it is secure, fast, and easy to implement software. The proposed algorithm use the fast operating 213-bit arithmetic shift register(ASR) to generate a binary sequence and produce 64-bit stream cipher by using simple logical operation in non linear transform. MS64 supports 128-bit key in encryption algorithm and satisfy with the safety requirement in modern encryption algorithm. In simulation result shows that MS64 is faster than a 32-bit stream cipher SSC2 in the speed of operation with small usage of memory thus MS64 can be used for mobile devices with fast ciphering.

• Journal of Korea Multimedia Society
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• v.7 no.3
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• pp.349-356
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• 2004

In this paper, a practical image security system using SA algorithm and 4-f optical correlator system is proposed. The encrypted image and key image with binary phase components are generated using an iterative SA algorithm. a decrypted image is found through the correlation of the encrypted and key images using 4-f optical correlator system. The encrypted and key images are consisted of binary phase components. So, it is easy to implement the optical security system using the proposed technique. And if we fix the encrypted image in the optical security system and change the key images, we get different images, so it is possible to apply to the distinguished authorization system using different key images. Computer simulations show that despite the binary phase components of the two images(encrypted and key image), decrypted images are generated.

• Journal of Korea Multimedia Society
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• v.17 no.10
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• pp.1182-1188
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• 2014

Recently, the research on database outsourcing has been actively done with the popularity of cloud computing. However, because users' data may contain sensitive personal information, such as health, financial and location information, the data encryption methods have attracted much interest. Existing data encryption schemes process a query without decrypting the encrypted databases in order to support user privacy protection. On the other hand, to efficiently handle the large amount of data in cloud computing, it is necessary to study the distributed index structure. However, existing index structure and query processing algorithms have a limitation that they only consider single-column query processing. In this paper, we propose a grid-based multi column indexing scheme and an encrypted query processing algorithm. In order to support multi-column query processing, the multi-dimensional index keys are generated by using a space decomposition method, i.e. grid index. To support encrypted query processing over encrypted data, we adopt the Hilbert curve when generating a index key. Finally, we prove that the proposed scheme is more efficient than existing scheme for processing the exact and range query.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.3
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• pp.49-61
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• 2004

In broadcast encryption schemes, traceability is a useful property to trace authorized subscribers, called traitors, who collude for manufacturing a pirate decoder. Unfortunately, this is usually achieved with a sacrifice of a privacy. Most traitor tracing schemes in the literature have been developed without considering a subscriber's anonymity, which is one of important requirements for electronic marketplaces to offer similar privacy as current marketplace. It would be unsatisfactory for the subscriber to reveal his/her identity to purchase multimedia contents. In this paper we propose an anonymous broadcast encryption scheme, where a user can subscribe anonymously and one purchases multimedia contents without giving a lot of information about his lifestyle, habits, and etc, but anonymity control is provided, i.e., a data supplier can date traitors.

• 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.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.11b
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• pp.873-876
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• 2002

최근 통신의 발달과 함께 그의 역효과로 정보의 유출에 관한 문제가 대두되고 있다. 이를 해결하기 위해 본 논문에서는 데이터를 저장하기 전 중요 데이터에 대해 대칭키, 즉 세션키를 이용하여 암호화를 하고 이 세션키를 비대칭키인 공개키와 개인키를 이용하여 암호화한다. 우선 세션키를 자신의 공개키로 암호화하여 저장하므로 데이터에 대한 접근을 하기 위해 필요한 세션키를 자신만이 볼 수 있도록 한다. 그렇게 하므로 데이터 암호화하는 속도를 빠르게 할 수 있고, 세션키를 따로 공개키로 암호화하여 저장하므로 보안성을 강화할 수 있다.

• Proceedings of the Korea Contents Association Conference
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• 2003.05a
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• pp.218-222
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• 2003

Internet has made it easer to get information, also distribute and exchange it among people. It brings about issues regarding intelligent property and copyright threats. h a multimedia commerce such as video-on-demand, Internet broadcasting services, only users who have rights for use of these services should be able to access and watch those video or movies In this paper, we propose DRM(Digital Right Management) system for P4 -based streaming and MP4 encryption algorithm for proposed DRM system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.799-802
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• 2007

Broadcast encryption has been applied to transmit digital information such as multimedia, software and paid TV programs on the open networks. This paper presents a method called Traitor Tracing to solve all these problems. Traitor tracing can check attackers and trace them. It also utilizes a proactive way for each user to have effective renewal cycle to generate keys.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.7C
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• pp.1007-1014
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• 2004

In this paper, H.235 based security mechanism for H.323 multimedia applications was implemented in embedded environment. H.235 covers authentication using HMAC-SHAI -96, authenticated Diffie-Hellman key exchange, security capability exchange, session key management for voice encryption, and encryption functions such as DES, 3DES, RC2. H.235-based mechanisms were also analyzed in terms of its security and possible attacks.