• The Transactions of the Korean Institute of Electrical Engineers P
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• v.54 no.4
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• pp.217-223
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• 2005

In this paper, we have proposed a secure dynamic ID allocation protocol using mutual authentication on the RFID tag. Currently, there are many security protocols focused on the low-price RFID tag. The conventional low-price tags have limitation of computing power and rewritability of memory. The proposed secure dynamic ID allocation protocol targets to the high-performance RFID tags which have more powerful performance than conventional low-price tag by allocating a dynamic ID to RFID using mutual authentication based on symmetric encryption algorithm. This protocol can be used as a partial solution for ID tracing and forgery.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.154-156
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• 2005

인터넷의 확산과 컴퓨터 간 상호연결성의 증대로 디지털 자원에 대한 유통 환경이 급속히 변화함에 따라 디지털 형태의 음악, 화상, 영상물, 출판물 등 멀티미디어 자료에 대한 수요가 급격히 증가하고 있다. 하지만 디지털 저작물은 품질에 대한 손상이 없이 복제가 가능하기 때문에 불법복제 방지를 위한 디지털 저작권 보호문제가 중요한 이슈로 대두되고 있다. 본 논문에서는 기존의 암호화 방법보다 다양한 키를 생성하는 알고리즘을 제안하며, 키 생성 알고리즘을 통해 각각 생성된 랜덤 대칭키를 서버에 저장하지 않는 기존의 시스템보다 보안성이 높은 암호화 방법을 제안한다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2018.06a
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• pp.225-226
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• 2018

홀로그램 콘텐츠의 정보보안을 위한 암호화 방법을 제안한다. 제안하는 암호화 기법은 실시간 처리를 위해 부분 홀로그램에 대하여 편향치를 더하고, 이중 프레넬 변환을 수행하여 에너지가 집중된 DC 영역을 획득한다. 이때 집중된 영역이 암호화 영역으로 적은 데이터롤 이용하여 고효율의 암호화를 수행한다. 제안한 기법은 기존 연구보다 변환하는 크기를 줄이기 때문에 같은 효율로 고속의 암호화를 수행할 수 있다. $1,024{\times}1,024$ 크기의 홀로그램을 $32{\times}32$ 부분홀로그램으로 구성하여 적용할 경우 약 18배 빠르게 처리할 수 있다.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.05a
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• pp.683-686
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• 2013

최근 인터넷을 이용한 금융거래가 활발해지면서 피싱이나 파밍과 같은 공격을 통한 개인정보 유출 사고가 빈번히 발생하고 있다. 특히 파밍의 경우, 공격자가 DNS 정보를 변조하여 사용자가 올바른 URL을 입력하더라도 악의적 사이트로 컴퓨터가 접속을 하기 때문에 위험성이 매우 높다. 이러한 공격들을 방지하기위하여 여러 연구가 진행되었지만, DNS 정보의 검증을 위한 추가적인 절차를 필요로 하거나 과도한 네트워크 트래픽을 유발할 수 있는 문제점을 가지고 있다. 따라서 본 논문에서는 이러한 문제점을 극복하고자 DNS 리소스 레코드(Resource Record)의 부분 암호화를 이용하여 DNS 변조 공격을 탐지 하는 프로토콜을 제안한다.

• Journal of Convergence for Information Technology
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• v.8 no.3
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• pp.63-69
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• 2018

Recently, healthcare services are using cloud services to efficiently manage users' healthcare data. However, research to ensure the stability of the user's healthcare data processed in the cloud environment is insufficient. In this paper, we propose a partial random encryption scheme that efficiently encrypts healthcare data in a cloud environment. The proposed scheme generates two random keys (p, q) generated by the user to optimize for the hospital medical service and reflects them in public key and private key generation. The random key used in the proposed scheme improves the efficiency of user 's healthcare data processing by encrypting only part of the data without encrypting the whole data. As a result of the performance evaluation, the proposed method showed 21.6% lower than the existing method and 18.5% improved the user healthcare data processing time in the hospital.

• Journal of the Korea Society of Computer and Information
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• v.26 no.4
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• pp.1-9
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• 2021

In this paper, we propose a training algorithm of support vector machine (SVM) with a sensitive variable. Although machine learning models enable automatic decision making in the real world applications, regulations prohibit sensitive information from being used to protect privacy. In particular, the privacy protection of the legally protected attributes such as race, gender, and disability is compulsory. We present an efficient least square SVM (LSSVM) training algorithm using a fully homomorphic encryption (FHE) to protect a partial sensitive attribute. Our framework posits that data owner has both non-sensitive attributes and a sensitive attribute while machine learning service provider (MLSP) can get non-sensitive attributes and an encrypted sensitive attribute. As a result, data owner can obtain the encrypted model parameters without exposing their sensitive information to MLSP. In the inference phase, both non-sensitive attributes and a sensitive attribute are encrypted, and all computations should be conducted on encrypted domain. Through the experiments on real data, we identify that our proposed method enables to implement privacy-preserving sensitive LSSVM with FHE that has comparable performance with the original LSSVM algorithm. In addition, we demonstrate that the efficient sensitive LSSVM with FHE significantly improves the computational cost with a small degradation of performance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.4
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• pp.642-648
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• 2006

In this paper, I have proposed a secure dynamic ID allocation protocol using mutual authentication on the RFID tag. Currently, there are many security protocols focused on the low-price RFID tag. The conventional low-price tags have limitation of computing power and rewritability of memory. The proposed secure dynamic ID allocation protocol targets to the high-performance RFID tags which have more powerful performance than conventional low-price tag by allocating a dynamic ID to RFID using mutual authentication based on symmetric encryption algorithm. This protocol can be used as a partial solution for ID tracing and forgery.

• Journal of Information Processing Systems
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• v.9 no.3
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• pp.405-424
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• 2013

This research paper proposes a secured, robust approach of information security using steganography. It presents two component based LSB (Least Significant Bit) steganography methods for embedding secret data in the least significant bits of blue components and partial green components of random pixel locations in the edges of images. An adaptive LSB based steganography is proposed for embedding data based on the data available in MSB's (Most Significant Bits) of red, green, and blue components of randomly selected pixels across smooth areas. A hybrid feature detection filter is also proposed that performs better to predict edge areas even in noisy conditions. AES (Advanced Encryption Standard) and random pixel embedding is incorporated to provide two-tier security. The experimental results of the proposed approach are better in terms of PSNR and capacity. The comparison analysis of output results with other existing techniques is giving the proposed approach an edge over others. It has been thoroughly tested for various steganalysis attacks like visual analysis, histogram analysis, chi-square, and RS analysis and could sustain all these attacks very well.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.05a
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• pp.548-551
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• 2013

디지털 콘텐츠가 대용량화됨에 따라, 부분암호화는 디지털 콘텐츠 보호를 위한 하나의 방안이 될 수 있다. 부분암호화 시에 고려해야할 사항 중 하나는 복호화를 위해 암호화된 부분의 정보를 별도로 관리해야하는 것이다. 부분암호화 정보의 관리가 제대로 이루어지지 않을 경우, 데이터가 완벽히 복호화 되지 않거나, 보안위협에 노출될 수 있으며, 데이터 전체를 암호화하는 것보다 오히려 더 많은 비용이 발생할 수 있다. 본 논문에서는 이러한 부분암호화 정보를 안전하고, 효율적으로 관리할 수 있는 의사난수생성기와 진리표를 이용한 부분암호화 기법을 제안한다. 제안하는 방법은 복호화 시에 암호화된 부분의 식별을 위해 의사난수생성기 초기화 값과 진리표만 필요하기 때문에 부분암호화 정보를 관리하는데 용이한 장점이 있다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.12 no.2
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• pp.147-152
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• 2002

SFLASH, one of the asymmetric signature schemes in NESSIE project, was suggested and accepted in the fat phase. In the latest, results about attacking the affine parts of SFLASH was published. In this paper, we have that an attacker knowing one linear part and two affine parts can easily forge signatures for arbitrary messages without information of the other linear part and the secret suing. It follows that the security of SFLASH depends only on the linear par, which is used in the last step when a signature is being generated. Also, we show that an attacker can obtain partial information of the linear part by the forging method using hem public key and secret elements and we discuss the length of secret key.