• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.4
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• pp.769-776
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• 2016

TELNET is vulnerable to network attack because it was designed without considering security. SSL/TLS and SSH are used to solve this problem. However it needs additional secure protocol and has no backward compatibility with existing TELNET in this way. In this paper, we have suggested STELNET(Secured Telnet) which supports security functionalities internally so that has a backward compatibility. STELNET supports a backward compatibility with existing TELNET through option negotiation. On STELNET, A client authenticates server by a certificate or digital signature generated by using ECDSA. After server is authenticated, two hosts generate a session key by ECDH algorithm. And then by using the key, they encrypt data with AES and generate HMAC by using SHA-256. After then they transmit encrypted data and generated HMAC. In conclusion, STELNET which has a backward compatibility with existing TELNET defends MITM(Man-In-The-Middle) attack and supports security functionalities ensuring confidentiality and integrity of transmitted data.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.6
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• pp.19-25
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• 2017

This paper deals with integer factorization of two prime p,q of SHA-256 secure hash value n for Bit coin mining. This paper proposes an algorithm that greatly reduces the execution time of Pollard's rho integer factorization algorithm. Rho(${\rho}$) algorithm computes $x_i=x^2_{i-1}+1(mod\;n)$ and $y_i=[(y^2_{i-1}+1)^2+1](mod\;n)$ for intial values $(x_0,y_0)=(2,2)$ to find the factor 1 < $gcd({\mid}x_i-y_i{\mid},n)$ < n. It however fails to factorize some particular composite numbers. The algorithm proposed in this paper applies multiple initial values $(x_0,y_0)=(2^k,2^k)$ and ($2^k,2$), $2{\leq}k{\leq}10$ to the existing Pollard's Rho algorithm. As a results, the proposed algorithm achieves both the factorization of all the composite numbers and the reduction of the execution time of Pollard's Rho by 67.94%.

• Proceedings of the Korea Multimedia Society Conference
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• 2002.05d
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• pp.920-925
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• 2002

급속히 고갈되어가는 IPv4의 주소 부족 문제를 해결하기 위하여, 차세대 인터넷 프로토콜 (IP)인 IPv6가 제안되었고 실용화 단계까지 진행되고 있다. IPv6에서의 요구 사항 중의 하나인 IPSec은 IPv4의 취약한 보안 기능을 강화하는 것이다. 현재 IPSec에서 반드시 구현되어야 할 암호화 알고리즘으로 MD5, SHA1, 3DES와 더불어 최근 표준안으로 채택된 AES(Rijndael)을 요구하고 있다. IPv6의 고속 수행을 위하여는 IPSec이 하드웨어로 구현될 필요성이 있으므로, 본 논문에서는 IPv6용 IPSec 칩에 탑재할 AES 하드웨어 모듈을 구현하였다. 제안된 하드웨어 모듈은 효율적인 알고리즘의 수행과 구현을 위하여, 암호화/복호화 단계가 동일한 구조로 동작하도록 설계하였으며, 가변적인 128, 196,256 비트의 키에 대하여 같은 로직을 사용하도록 설계하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.227-228
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• 2010

Generated One-Time Password (OTP) is used only once. This attributes is to safety than to repeated use the same password. Recently, Park's proposed on "Design of A One-time Password Generator on A Mobile Phone Providing An Additional Authentication for A Particular Transaction" use challenge-response based one-time password generator. However, Challenge exchange problem and currently OTP the same security level. In this paper, Park's proposed OTP generator design for us analysis. And then presents a resolution to the problem and new system logic. New system strong to Man-In-Middle attack and replay attack. In addition, OTP security level is higher.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.5
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• pp.179-186
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• 2018

Currently, apps that run point management systems can accumulate, use, and view points, but there are no apps that present gifts to other users or pay a Dutch fee for points. In addition, although the penetration rate of smartphones is increasing, it is inconvenient to put point-related cards into wallets rather than using apps. Of course, to run your app's services, It requires a lot of research and development, but it has the advantage of being convenient to customers. Therefore, the point app management system to be mentioned in this paper can alleviate user inconvenience and feel the convenience of point management. Point management The configuration of the app system allows you to launch an app using an Android device and manage the points of all services. You can also perform functions such as earning, using, and viewing points related to points.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.1
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• pp.250-256
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• 2017

Recently, the use of mobile devices has increased in order to provide a variety of services, and thus there has been a surge in the number of application malicious attacks on the Android platform. To resolve the problem, the domestic financial sector has been introducing the app anti-tamper solution based on cryptographic algorithms. However, since the capacity of apps installed in smartphones continues to increase and environments with limited resources as wearables and IoTs spread, there are limitations to the processing speed of the anti-tamper solutions. In this paper, we propose a novel anti-tamper solution by using lightweight hash function LEA and LSH. We also present the test results of a simulation program that implements this method and compare the performance with anti-tamper solutions based on the previous cryptographic algorithms.

• Annual Conference of KIPS
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• 2011.04a
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• pp.113-116
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• 2011

최근 IT 기술의 급격한 발전으로 개인정보, 환경 등 다양한 정보를 수시로 수집 및 관리하면서 사용자가 원할시 즉각적인 정보서비스를 제공하고 있다. 그러나 유 무선상의 데이터 전송은 정보의 도청, 메시지의 위 변조 및 재사용, DoS(Denial of Service)등 외부의 공격으로부터 쉽게 노출된다. 이러한 외부 공격은 개인 프라이버시를 포함한 정보서비스 시스템 전반에 치명적인 손실을 야기 시킬 수 있기 때문에 정보보호 시스템의 필요성은 갈수록 그 중요성이 부각되고 있다. 현재까지 정보보호 시스템은 소프트웨어(S/W), 하드웨어(ASIC), FPGA(Field Progr- ammable Array) 디바이스를 이용하여 구현되었으며, 각각의 구현방법은 여러 가지 문제점이 있으며 그에 따른 해결방법이 제시되고 있다. 본 논문에서는 다양한 환경에서의 정보보호 서비스를 제공하기 위한 재구성형 SoC 구조를 제안한다. 제안된 SoC는 비밀키 암호알고리즘(AES), 암호학적 해쉬(SHA-256), 공개키 암호알고리즘(ECC)을 수행 할 수 있으며, 마스터 콘트롤러에 의해 제어된다. 또한 정보보호 시스템이 요구하는 다양한 제약조건(속도, 면적, 안전성, 유연성)을 만족하기 위해 S/W, ASIC, FPGA 디바이스의 모든 장점을 최대한 활용하였으며, MCU와의 효율적인 통신을 위한 I/O 인터페이스를 제안한다. 따라서 제안된 정보보호 시스템은 기존의 시스템보다 다양한 정보보호 알고리즘을 지원할 뿐만 아니라 속도 및 면적에 있어 상충 관계를 개선하였기 때문에 저비용 응용뿐만 아니라 고속 통신 장비 시스템에도 적용이 가능하다.