• Journal of Information Technology Application
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• v.1 no.3_4
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• pp.91-112
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• 1999

대부분의 암호이론은 공개되어 있기 때문에 정보보안 기술의 안전성은 암호 알고리즘과 키 길이에 의존성이 크다. 본 논문에서는 해쉬함수와 카오스 함수를 이용하여 암·복호화를 위한 권장 키 길이보다 작은 길이의 일회성을 갖는 공개키와 비밀키를 생성하여 공개키 암호 알고리즘의 대표격인 RSA 암호방식에 적용하여 본다. 소인수 분해 알고리즘의 개선·발전과 시스템의 처리속도 증가에서 오는 키길이 증가 문제를 해결하므로 스마트 카드와 같은 제한된 메모리에서 실용적으로 사용할 수 있을 뿐만 아니라, 암·복호화를 수행하는 처리 시간을 단축 시킬 수 있으며, 키 관리면에서도 여러개의 공개키/비？키를 사용하는 경우보다 실용적이다.

• Korean Journal of Optics and Photonics
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• v.14 no.6
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• pp.636-642
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• 2003

We proposed the optical system using two divided halftone images to hide the original image and a joint transform correlator. The encryption procedure is performed by the Fourier transform of the product of each divided image by visual cryptography and the same random image which is generated by computer processing. As a result, we can obtain two Fourier divided images which are used as the encrypted image and the decrypting key, respectively. In the decryption procedure, both the encrypted image and the decrypting key are located on the joint input plane. Then the original image is reconstructed on a CCD camera which is located in the output plane. An autocorrelation term of joint transform correlator contributes to decrypt the original image. To demonstrate the efficiency of the proposed system, computer simulations and noise analysis are performed. The result show that the proposed system is a very useful optical certification system.

• Journal of Digital Contents Society
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• v.9 no.2
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• pp.331-339
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• 2008

This paper presents the development of certain highly efficient and accurate system for producing animation key data for 3D lip-synch animation. The system developed herein extracts korean phonemes from sound and text data automatically and then computes animation key data using the segmented phonemes. This animation key data is used for 3D lip-synch animation system developed herein as well as commercial 3D facial animation system. The conventional 3D lip-synch animation system segments the sound data into the phonemes based on English phonemic system and produces the lip-synch animation key data using the segmented phoneme. A drawback to this method is that it produces the unnatural animation for Korean contents. Another problem is that this method needs the manual supplementary work. In this paper, we propose the 3D lip-synch animation system that can segment the sound and text data into the phonemes automatically based on Korean phonemic system and produce the natural lip-synch animation using the segmented phonemes.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.3B
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• pp.220-230
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• 2011

Mobile RFID which integrates mobile network with RFID technique is the technique to get the information of products by transmitting the identifier through mobile network after reading the identifier of RFID tag. It attached on the equipment as the mobile phone. However, mobile RFID has the privacy-related problem among requested secure problems required from the existing RFID. In this paper, the random key created by mobile RFID reader and Tag during the inter-certificating and initialization procedure for mobile RFID users to receive tag information from backend server securely is divided into random sizes and any information on the tag which requires the protection of privacy shouldn't be provided to anyone. In performance analysis, previous protocol used modulo operation in registration and login computation. But the proposed protocol has higher efficiency in saving space and computation volume than MARP scheme and Kim. et. al scheme because our protocol is accomplished by mutual authentication and registering user information through one-way hash function.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.6A
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• pp.1107-1116
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• 2001

고속 IP 주소 룩업(lookup)은 고속 인터넷 라우터의 성능을 좌우하는 주요 요소이다. LPM(longest prefix matching) 탐색은 IP 주소 룩업에서 가장 시간이 많이 걸리는 부분이다. PICAM은 고속 LPM 탐색을 위한 파이프라인 CAM 구조로서, 기존 CAM(content addressable memory, 내용 주수화 메모리)을 이용한 방법보다 룩업 테이블의 갱신속도가 빠르면서도 LPM 탐색율이 높은 CAM 구조이다. PICAM은 3단계의 파이프라인으로 구성된다. 단계 1 및 단계 2의 키필드분할수 및 매칭점의 분포에 따라 파이프라인의 성능이 좌우되며, LPM 탐색율이 달라질 수 있다. 본 논문에서는 PICAM의 파이프라인 성능모델을 제시하고, 이산사건 시뮬레이션(discrete event simulation)을 수행하여, 최적의 PICAM 구조를 도출하였다. IP version 4인 경우 키필드분할수를 8로 하고, 부하가 많이 걸리는 키필드블록을 중복 설치하는 것이 최적구조이며, IP version 6인 경우 키필드블록의 개수를 16으로 하는 것이 최적구조다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.269-272
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• 2005

For the efficient image encryption, we proposed the encryption algorithm using the chaotic function and elementary matrix operation defined on the bit plane decomposition. Though the chaotic encryption algorithm is faster than block encryption, it uses a real number computation. In this sense, we use the row and column operations on the bit-plane decomposed images combined with logistic function for the recursive rounding number, too.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.5
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• pp.23-36
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• 2004

This paper presents a password based authentication and key exchange protocol which can be used for both authenticating users and exchanging session keys for a subsequent secure communication over an untrusted network. Our idea is to increase a randomness of the password verification data, i.e., we split the password, and then amplify the split passwords in the high entropy-structured password verification data. And in order to prevent the verifier-compromised attack, we construct our system such that the password verification data is encrypted with the verifier's key and the private key of verifier used to encrypt it is stored in a secure place like a smart cards. Also we propose the distributed password authentication scheme utilizing many authentication servers in order to prevent the server-compromised attack occurred when only one server is used. Furthermore, the security analysis on the proposed protocol has been presented as a conclusion.

• 건강소식
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• v.35 no.3
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• pp.28-29
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• 2011

"우리 아이 얼마나 더 자랄까?"새로운 학기가 시작되면 부모들의 관심거리는 자녀 성적과 함께 자녀 키에 쏠린다. 줄곧 맨 앞자리에 앉는 자녀를 둔 부모일수록 더욱 그렇다. 1년에 4cm 이내로 자라거나, 성장기임에도 지난해 옷을 그대로 입는다면 성장 지연이 의심된다.

• Journal of KIISE:Computer Systems and Theory
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• v.27 no.3
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• pp.345-351
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• 2000

This paper presents a right management scheme using secret splitting protocol. Right management schemes combat piracy of proprietary data (such as digital music). In these schemes, encryption has been used and it is essential to protect the keys used in encryption. We introduce a new key protection method in which a secret encryption key is generated using both user's hardware-dependent unique information (such as MAC address) and cryptographically secure random bit strings provided by data owner. This scheme prevents piracy by checking hardware-dependent information during rendering and improves the secrecy of the data by individualizing the encryption key for each data.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10a
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• pp.766-768
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• 2003

현대는 인터넷의 범람이라고 할 수 있을 만큼 세계의 곳곳에서 많은 사람들이 인터넷을 통해 여러 분야에서 사용하고 있다. 이처럼 인터넷을 이용하는데 있어 개인의 정보를 보호해야 하는 문제가 대두되고 있다. 기존의 암호화에 사용하는 키는 소인수 분해, 이산수학, 타원곡선등과 같이 수학적 이론에 바탕을 두어 생성되었다. 본 논문에서는 빛의 물리적인 성질 중의 하나인 간섭과 회절에 의해 생성되는 고유의 무늬인 무아레 무늬의 고유 값을 암호화를 위한 키로 사용하도록 제안하였다.