• Journal of the Korea Institute of Information Security & Cryptology
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• v.1 no.1
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• pp.16-28
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• 1991

Knapsack public-key cryptosystems are based on the knapsack problem which is NP-complete. aii of the knapsack problem, are known to be insecure. However, the Chor and Rivest knapsack cryptosystem based on arithmetic in finite field is secure against all known cryptosystem based on arithmetic in a finite field is secure against all known cryptanalytic attacks. We suggest a new msthod of attack on knapsack cryptosystem which is based on the relaxation of a quadratic 0-1 integer optimization problem. We show that under certain condirions some bits of the solution of knapsack problem can be determined by using persistency property of linear relaxation. Also we propose a new Chor-Rivest system, this new cryptosystem reduces the number of calculation of discrete logarithms which are necessary for the implemention in a multi-user system.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.2
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• pp.139-147
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• 2011

More convenient and value-added application services can be provided to user in case of using location-based service on Smart phone. However, privacy problem will be happen when an application disclosures the personal location information. Therefore, each user should securely control and manage his own personal location information by specifying access control list and profiles. In this study, we implemented personal location information self-control protocol and developed secure personal location management system with OTP based authentication procedure.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.63-65
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• 2021

This paper describes an integrated H/W-S/W implementation of elliptic curve digital signature algorithm (EC-DSA) using a security system-on-chip (SoC). The security SoC uses the Cortex-A53 APU as CPU, and the hardware IPs of high-performance elliptic curve cryptography (HP-ECC) core and SHA3 (secure hash algorithm 3) hash function core are interfaced via AXI4-Lite bus protocol. The signature generation and verification processes of EC-DSA were verified by the implementation of the security SoC on a Zynq UltraScale+ MPSoC device.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2002.11a
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• pp.219-224
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• 2002

In this paper, after designing an efficient and secure Internet voting protocol (called as “votopia”) based on modified Ohkubo et. al.'s scheme [8] under Public Key Infrastructure (PKI), we have implemented this system and served via the Internet to select the Most Valuable Players and Best Goal Keepers of 2002 FIFA World Cup Korea/Japan$\^$TM/. The sketch of voting protocol, practical implementation and voting result arc described.

• Proceedings of the Korea Multimedia Society Conference
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• 2003.11b
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• pp.990-993
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• 2003

본 논문은 다중 사용자가 컴퓨터 시스템을 이용하려는 사용자의 신원을 확인하는 방법으로서 타인의 관찰로부터 노출되기 쉬운 패스워드의 약점들을 일소하고, 시스템의 안전성을 높이기 위한SPS(Secure Password System)라는 패스워드 시스템을 제안하고자 한다. SPS는 쉬운 실행과 낮은 가격을 포함한 전통적 패스워드 시스템의 대부분의 이점들을 받아들였고, 또한 안정성을 가지고 있으면서 전통적인 패스워드 시스템에 쉽게 이식될 수 있다. 제안한 SPS는 실험 결과 침입자의 온라인 사전적 공격과, 클라이언트에서의 패스워드 노출에 대해서 아주 높은 안전성을 보여 주었다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.657-659
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• 2011

Given the security and privacy problems in the application of Radio Frequency Identification(RFID), this paper is proposed a kind of novel security framework, aiming to find a better mechanism in security and privacy problems. This paper reviews the relative work of RFID security mechanisms, then, the overall design scheme and modularized implementation of a secure RFID system based on trusted computing technologies is presented.

• Journal of information and communication convergence engineering
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• v.6 no.1
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• pp.64-67
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• 2008

VoIP is vulnerable to attack since it uses the Internet to which many people connect simultaneously. In this paper, we designed and implemented a Wireless VoIP + VPN system with which secure telephone calls are possible using the open project SIP VoIP Gateway, 'Asterisk' and 'OpenVPN'.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.1169-1174
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• 1991

In conventional geographic mapping system, it is needed to input many already existing geographic map into computer system for secure and efficient maintence. Because of large map data, it is required to construct layers from map image for easy display, fast retreval and efficient storage. Thus this paper represents a method of the extracting features from contour map and constructing three layers. The layers are symbol, building, contour line. Experimental results are presented confirming the method's high extraction.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.203-206
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• 2003

네트워크 상에서 송수신되는 데이터를 외부의 침입으로부터 보호하는 것은 매우 중요하며, 그 중 데이터의 무결성을 검증하고 보장하기 위한 방법으로 SSL(Secure Socket Layer)을 사용한다. 본 논문에서는 클라이언트와 서버간에 송수신되는 데이터의 무결성이 위배되었을 경우 그 정보를 검증 및 관리할 수 있도록 OpenSSL을 이용한 무결성 위배 데이터 검증 및 관리 시스템을 구성하고, 검증된 데이터를 IDS(Intrusion Detection System)로 전송하여 침입 탐지 정보와 무결성 검증 정보를 통합적으로 관리할 수 있는 IDS 통합 시스템을 제안 및 설계하였다.

• Proceedings of the KIEE Conference
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• 2002.11c
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• pp.542-545
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• 2002

Position transfer and turning rotation between fingerprint and inputted fingerprint that is registered in automatic fingerprint recognition system are one of main cause that mistaken acknowledgment expression happens. Therefore, in this research, conformity algorithm development that do it so that is unrelated in position translation and rotation of fingerprint at feature point conformity step to secure higher correct recognition rate.