• Proceedings of the Korea Information Processing Society Conference
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• 2014.11a
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• pp.495-498
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• 2014

최근 스마트폰을 이용한 인터넷 사용이 증가하면서 카페나 영화관과 같은 공공장소에 많은 Access Point(AP)들이 설치되어 있다. 하지만 이러한 AP 대부분이 외부 공격에 무방비하게 노출되어 위험성이 대두되고 있다. 대표적인 공격으로 사용자와 AP간 통신에 끼어들어 데이터를 도청하거나 위 변조하는 Man-In-The-Middle(MITM) 공격이 있다. MITM 공격에 대한 대응책으로 통신간 암호화가 있지만, 모든 통신에 암호화를 적용하는 것은 많은 비용이 발생하기 때문에 현실적으로 불가능하다. 실제로 구글 플레이스토어에 등록된 100개의 무료 인기 어플리케이션 중 모든 메시지에 암호화 통신을 사용하는 어플리케이션은 없으며, 부분적으로 사용하는 어플리케이션은 43개임을 확인하였다. 본 논문에서는 앞서 설명한것과 같이 통신간 암호화를 하지 않는 어플리케이션을 MITM 공격으로부터 보호하기 위한 메시지 인증 기반 무결성 검증 방법을 제안하여 안전한 어플리케이션-서버 통신 모델 개발에 기틀을 마련한다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.4
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• pp.109-115
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• 2010

Differential Power Analysis (DPA) is well known as one of efficient physical side-channel attack methods using leakage power consumption traces. However, since the power traces usually include the components irrelevant to the encryption, the efficiency of the DPA attack may be degraded. To enhance the performance of DPA, we introduce a pre-processing technique which extracts the encryption-related parts from the measured power consumption signals. Experimental results show that the DPA attack with the use of the proposed pre-processing method detects correct cipher keys with much smaller number of signals compared to that of the conventional DPA attack.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.3
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• pp.235-241
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• 2017

With the coming of the digital era, encryption has become common in everyday life. Almost anyone can easily acquire encryption software and use it to prevent unwanted third parties from accessing one's private information. However, the spread of encryption has also seriously hindered law enforcement during the investigation of cybercrimes, which hides incriminating digital evidence in encrypted hard drives and files. Therefore, many countries have attempted to compel criminals to decrypt encrypted evidence and it has been inevitable to examine privilege against self-incrimination as basic right on the side of constitution. This study analyzed the past court decisions on the issue of compelled decryption in the US and whether the Government can compel a defendant to disclose his password in Korean legal system on the constitutional side. Finally, this study suggests an approach to create a legal procedure to make it a crime for a suspect or defendant to refuse to disclose his password to law enforcement for criminal cases in Korea.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.11
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• pp.1554-1561
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• 2018

This paper surveys the DDS, a real - time communication middleware, and proposes ways to improve the DDS secure communication performance. DDS is a communication middleware standard by the OMG. The OMG has released the DDS Security standard to resolve the security issues. The security performance of DDS can be considered into transmission speed and confidentiality. In terms of confidentiality, AES-GCM, currently the encryption algorithm specified by DDS Security, is a very strong encryption algorithm, but there are well known weaknesses associated with authentication. In terms of speed, The computational load for the security function is a restriction to use DDS in systems which requires real-time performance. Therefore, in order to improve the DDS security, algorithms that are faster than AES-GCM and strong in encryption strength are needed. In this paper, we propose a DDS message encryption method applying AES-OCB algorithm to meet these requirements and Compared with the existing DDS, the transmission performance is improved by up to 12%.

• Journal of Broadcast Engineering
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• v.17 no.2
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• pp.374-387
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• 2012

In this paper, we implement a new hardware for finding the significant coefficients of a digital hologram and ciphering them using discrete wavelet packet transform (DWPT). Discrete wavelet transform (DWT) and packetization of subbands is used, and the adopted ciphering technique can encrypt the subbands with various robustness based on the level of the wavelet transform and the threshold of subband energy. The hologram encryption consists of two parts; the first is to process DWPT, and the second is to encrypt the coefficients. We propose a lifting based hardware architecture for fast DWPT and block ciphering system with multi-mode for the various types of encryption. The unit cell which calculates the repeated arithmetic with the same structure is proposed and then it is expanded to the lifting kernel hardware. The block ciphering system is configured with three block cipher, AES, SEED and 3DES and encrypt and decrypt data with minimal latency time(minimum 128 clocks, maximum 256 clock) in real time. The information of a digital hologram can be hided by encrypting 0.032% data of all. The implemented hardware used about 200K gates in $0.25{\mu}m$ CMOS library and was stably operated with 165MHz clock frequency in timing simulation.

• Proceedings of the CALSEC Conference
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• 1999.07b
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• pp.475-490
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• 1999

전자상거래는 거래의 많은 부분을 차지할 수 있는 잡지, 신문, 음악, 소프트웨어 등의 거래에 필요한 소액 지불수단이 필요하다. 이러한 요구조건을 만족시기 위해서는 과도한 암호화 부담을 줄이고 처리비용을 낮추는 것이 필요한데 가장 잘 된 프로토콜로는 Millicent가 꼽인다. 본 연구에서는 Millicent의 구현 방안에 대하여 고려해 본다.

• Journal of Digital Convergence
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• v.14 no.10
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• pp.295-302
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• 2016

Many countries, especially ICT powers, are supporting IoT-based technology at a national level and this technology is actively being researched in the businesses and research institutes in an aim to develop technology and create an ecosystem. Roads in the Seoul city are building public facilities based on IoT to provide various services and conveniences for the users. However, for the full-fledged introduction and development of IoT, there are many cases where infringement on security and privacy and threat for life and safety happen. Also, as the IoT environment includes various environment technologies such as the existing sensor network, heterogeneous communication network, and devices optimized for the IoT environment, it inherits the existing security threat and various attack techniques. This paper researches the attribute based encryption technology for safe communication in the IoT environment. The data collected from the device is transmitted utilizing the attribute based encryption and by designing the key generation protocol, grades and authorities for the device and users are identified to transmit safe messages.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.196-198
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• 2003

In this paper, Rijndal cipher algorithm is implemented by a hardware. It is selected as the AES(Advanced Encryption Standard) by NIST. The processor has structure that round operation divided into 2 subrounds and subrounds are pipelined to calculate efficiently. It takes 5 clocks for one-round. The AES-128 cipher algorithm is implemented for hardware by ALTERA FPGA, and then, analyzed the performance. The AES-128 cipher algorithm has approximately 424 Mbps encryption rate for 166Mhz max clerk frequency. In case of decryption, it has 363 Mbps decryption rate for 142Mhz max clock frequency.

• The KIPS Transactions:PartD
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• v.11D no.7 s.96
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• pp.1537-1542
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• 2004

Various studies to increase customer satisfaction of a web based system are performed actively. Also in recent days an interest about the personalization that supporting a order type service on customer's viewpoint was raised. So the studies supporting the personalization is required in a web-based marketing system. In this study, we designed an intelligent recommendation system which supporting one to one web marketing using cross selling. The proposed system used an intelligent data mining method as a concurrent cross selling and a sequential cross selling. Also, In experiment on the prototype, we show a proposed system was usable in an practical system applying the mining result.

• Convergence Security Journal
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• v.11 no.3
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• pp.47-54
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• 2011

To protect SVC(Scalable Video Coding) media, the encryption mechanism need to consider two fundamental issues; First, What is to be encrypted? Second, When encryption is performed with respect to compression? In this paper, we analyze the several encryption approaches with regard to the above issue. And we propose hybrid-based protection mechanism. This mechanism ensures the media scalability, layered access control and reuse protected content. In this experiment the proposed mechanism generates under 3% security overhead against standard scalable video coding.