• Proceedings of the Korean Society for Information Management Conference
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• 2000.08a
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• pp.181-184
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• 2000

전자상거래의 급격한 성장에 따라 인터넷이라는 광용 네트워크에서 보다 안전한 지불수단을 필요로 하게 되었다. 현재 SSL을 이용한 정보보호 방법과 SET를 이용한 지불 프로토콜이 표준화 및 상용화되어 있다. 그러나 SSL은 신용카드나 직불카드 번호와 같은 중요한 정보들이 사용자의 의지와 상관없이 여러 통로로 노출될 수 있으며 거래 당사자들의 인증수단이 취약하다는 단점이 있다. SET 역시 프로세스들이 복잡하고 비용 등에 부담을 주고 있다. 새로운 대안으로 SSL 기반에 특정한 상황에 SET으로 대체하는 것과 SSL에 인증기능을 강화하는 등의 새로운 연구들이 이루어지고 있다. 본 연구에서는 SET 프로토콜 기반의 새로운 지불 시스템을 제안한다.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10a
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• pp.760-762
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• 2003

인터넷을 비롯한 대부분의 패킷스위칭 네트워크는 IP(Internet Protocol)을 기반으로 하고 있으나, IP는 기본적으로 보안에 취약하게 설계되어 보안이 필요한 통신에 사용하는데는 어려움이 있다. IPSec(IP Security)은 IP 트래픽에 대한 이러한 보안문제를 극복하기 위해 생겨났으며, 방화벽과 결합된 형태로 가장 널리 쓰이고 있는 VPN(Virtual Private Network) 제품의 하나이다. 그러나 IPSec 자체의 문제점이 대두되고, Web-based Service가 영역을 넓혀가면서 기존의 웹 보안 프로토콜인 SSL이 VPN의 새로운 형식으로 나타나고 있다. 본 고에서는 이러한 SSL VPN의 모델을 IPSec VPN과 비교하여 분석하고자 한다.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10a
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• pp.730-732
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• 2004

1996년 P. Kocher에 의해 시차공격(Timing attack)이 제안된 후 일반적인 RSA구현 시 시간차를 줄이기 위해 중국인의 나머지 정리와 Montgomery 알고리즘과 같은 다양한 방법들이 적용되어왔다. 2003년 D. Brumley와 D. Boneh가 OpenSSL(2)에서 구현된 RSA 알고리즘을 분석하여 시차공격(3)이 가능함을 보였다. 본 논문은 이들의 방법을 OpenSSL을 기반으로 하는 서버를 대상으로 구현한 실험 결과를 보인다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.1
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• pp.145-153
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• 2018

SSL (Secure Socket Layer) and TLS (Transport Layer Security) are widely used protocols for secure and encrypted communication over a computer network. However, there have been reported several security vulnerabilities of SSL/TLS over the years. The vulnerabilities can let an adversary carry out critical attacks on SSL/TLS enabled servers. In this paper, we have developed a system which can periodically scan SSL/TLS vulnerabilities on internal network servers and quickly detects, reports and visualizes the vulnerabilities. We have evaluated the system on working servers of Naver services and analyzed detected vulnerabilities. 816 vulnerabilities are found on 213 internal server domains (4.2 vulnerabilities on average) and most vulnerable servers are not opened to public. However, 46 server domains have old vulnerabilites which were found 2016. We could patch and response to SSL/TLS vulnerabilites of servers by leveraging the proposed system.

• The KIPS Transactions:PartC
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• v.11C no.2
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• pp.163-170
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• 2004

The additional mechanism Is required to set up a secure connection among the communication subjects in the internet environment. Each entity should transfer and receive the encrypted and hashed data to guarantee the data integrity. Also, the mutual authentication procedure should be processed using a secure communication protocol. The SSL/TLS is a protocol which creates the secure communication channel among the communication subjects and sends/receives a data. Although the OpenSSL which implements the TLS is using by many developers and its stability and performance are proved, it has a difficulty in using because of its large size. So, this Paper designs and implements the secure communication which the users can use easily by modification works of OpenSSL library API. We proved the real application results using the DRM client/server case which supports a secure communication using the implemented API.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.9
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• pp.813-819
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• 2011

In this paper, a new design method of a tunable oscillator using a suspended-stripline resonator is presented. The negative resistance of an FET mounted on microstrip line(MSL) is combined with a high Q suspended-stripline(SSL) resonator to produce a tunable oscillator with good phase noise. The new MSL-SSL transition facilitates the easy connection between the MSL-based circuits and the SSL module. The proposed oscillator is also frequency-tunable using a tuner located on the top of the SSL housing. The measured phase noise of the implemented oscillator at 3.37 GHz is -108.03 dBc@100 kHz and -135.09 dBc@1 MHz with 50 MHz of frequency tuning.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.3
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• pp.661-666
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• 2016

The Internet of Things (IoT) is an infrastructure of physical objects that could be connected to the Internet. Most of these are low performance to ensure a reasonable cost for the smart physical objects. Thus, these devices usually use a lightweight messaging protocol: message queue telemetry transport with SSL/TLS. Cipher suites in device are fixed by default and selected based on preference in SSL/TLS. However, the selected cipher suite provides high security level more than expected. This limitation causes energy waste and overhead of devices. In order to counter this problem, we proposed fuzzy logic based cipher suite decision method to improve energy efficiency. Our proposed method saved 36.03% energy.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.3
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• pp.307-314
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• 2010

In this paper, a novel ultra-wideband microstrip-to-suspended stripline(SSL) transition is proposed, and SSL filters with low-loss and high selectivity have been realized using this transition. Since the proposed transition has low-loss and wide bandwidth characteristic, the design procedure of SSL filters become simplified. Additionally, the designed filters do not require extra time-consuming tuning. As design examples, SSL low-pass and high-pass filters have been implemented, and a implemented bandpass filter with connection of the low and high-pass filters performs 2.3~10.5 GHz bandwidth with less than 1.2 dB insertion loss and high selectivity.

• Journal of Internet Computing and Services
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• v.5 no.6
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• pp.45-58
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• 2004

This paper consists of two parts, One is the ECC( GF(2/sup m/)) algorithm to improve the security strength and the processing time of SSL VPN and the other is the WLCAPT algorithm instead of LSNAT for the security strength of virtual server. In general when corporates use SSL protocol in order to build VPN, they use RSA algorithm with the problem of security and processing time about authentication and confidentiality, In this paper, a shared public key is generated with ECSPK which uses ECC( GF(2/sup m/)) algorithm to improve the security and processing time instead of RSA In addition, WLCAPT algorithm proposed in this paper is applied to virtual server which resides in the server side and then after NAT translation, the actual server of headquarter is securely communicated with it.

• Proceedings of the Korean Information Science Society Conference
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• 2002.04a
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• pp.781-783
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• 2002

Signcryption 알고리즘은 전자서명과 암호화를 한번의 연산으로 수행할 수 있는 알고리즘으로 기존의 방식인 전자서명과 암호화를 개별적으로 수행하는 방식에 비해 효율성이 우수하다고 알려져 있다. 본 논문에서는 Signcryption 알고리즘을 SSL에 적용하는 방법을 기술하고 적용된 방법이 효율성 측면에서 우수함을 보인다.