• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제6권8호
• /
• pp.1982-1997
• /
• 2012

Authenticated multiple key agreement protocols not only allow participants to agree the multiple session keys within one run of the protocol but also ensure the authenticity of the other party. In 2011, Dehkordi et al. proposed an identity-based authenticated multiple key agreement protocol. In this paper, we demonstrate that Dehkordi et al.'s protocol is vulnerable to impersonation attacks. Furthermore, we have found that their protocol cannot provide perfect forward security or mutual security. Then we propose an identity-based authenticated multiple key agreement protocol which removes the weaknesses of the Dehkordi et al.'s protocol. Compared with the multiple key agreement protocols in the literature, the proposed protocol is more efficient and holds stronger security.

• 한국산업정보학회논문지
• /
• 제16권1호
• /
• pp.9-19
• /
• 2011

Secure and efficient authentication schemes over insecure networks have been a very important issue with the rapid development of networking technologies. Wang et al. proposed a remote user authentication scheme using smart cards. However, recently, Chen et al. pointed out that their scheme is vulnerable to the impersonation attack and the parallel session attack, and they proposed an enhanced authentication scheme. Chen et al. claimed that their scheme is secure against the various attacks. However, we have found that their scheme cannot resist the parallel attack and the stolen smart card attack. Therefore, in this paper, we show the security flaws in Chen et al.'s scheme and propose an improved remote user authentication scheme using tamper-resistant smart cards to solve the problem of Chen et al.'s scheme. We also analyze our scheme in terms of security and performance.

• Journal of information and communication convergence engineering
• /
• 제15권3호
• /
• pp.151-159
• /
• 2017

Steganography, which is popular as an image processing technology, is the art of using digital images to hide a secret message in such a way that its existence can only be discovered by the sender and the intended receiver. This technique has the advantage of concealing secret information in a cover medium without drawing attention to it, unlike cryptography, which tries to convert data into something messy or meaningless. In this paper, we propose two efficient least significant bit (LSB)-based steganography techniques for designing an image-based steganography system on chip using hardware description language (HDL). The proposed techniques manipulate the LSB plane of the cover image to embed text inside it. The output of these algorithms is a stego-image which has the same quality as that of the original image. We also implement the proposed techniques using the Altera field programmable gate array (FPGA) and Quartus II design software.

• 한국정보처리학회:학술대회논문집
• /
• 한국정보처리학회 2017년도 춘계학술발표대회
• /
• pp.203-206
• /
• 2017

최근 휴대전화 문자스팸 차단 강화로 인한 풍선효과로 휴대전화 음성스팸이 지속적으로 증가하고 있고, 2015년 3월부터는 음성스팸 건수가 문자스팸 건수를 역전해서 급속도로 증가하고 있어 효율적으로 음성스팸을 차단할 수 있는 시스템 구축의 필요성이 대두되고 있다. 이에, 음성스팸 신고번호와 음성스팸 가상 트랩(실제 존재하지 않는 가상의 휴대전화번호를 적용)을 통해 탐지된 내용을 기반으로 음성스팸 전화번호 차단리스트를 생성하고 이를 이통사에게 제공하여 일정기간 동안 음성호를 차단하는 음성스팸 실시간 차단시스템을 설계하고자 한다.

• 한국콘텐츠학회:학술대회논문집
• /
• 한국콘텐츠학회 2003년도 춘계종합학술대회논문집
• /
• pp.209-213
• /
• 2003

컨텐츠 암호화를 통하여 컨텐츠를 보호하고 통제하려는 DRM 관련 기술은 현재 몇 가지 제품으로 상용화 되어 서비스 되고 있는 상황이다. 하지만 현재지 DRM기술은 최종 사용자로부터의 컨텐츠 보호에 중점을 두고 있어, 컨텐츠 유통에 참여하는 창조자, 제공자, 분배자 등 주체들에게 저작권의 보호 및 관리 문제, 올바른 유통 체계 확립 문제 등을 효과적으로 해결할 수 있는 수단을 제공하지 뭇하고 있다. 본 논문은 DRM을 기반으로 컨텐츠를 유통하기 위한 컨텐츠와 메타데이터에 대한 처리 방법을 제시하고 다양한 컨텐츠 유통 모델에서 쉽게 컨텐츠를 유흥시킬 수 있는 환경을 제안한다.

• Journal of information and communication convergence engineering
• /
• 제7권2호
• /
• pp.98-106
• /
• 2009

Process Control Systems (PCSs) or Supervisory Control and Data Acquisition (SCADA) systems have recently been added to the already wide collection of wireless sensor networks applications. The PCS/SCADA environment is somewhat more amenable to the use of heavy cryptographic mechanisms such as public key cryptography than other sensor application environments. The sensor nodes in the environment, however, are still open to devastating attacks such as node capture, which makes designing a secure key management challenging. In this paper, a key management scheme is proposed to defeat node capture attack by offering both forward and backward secrecies. Our scheme overcomes the pitfalls which Nilsson et al.'s scheme suffers from, and is not more expensive than their scheme.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제16권1호
• /
• pp.118-125
• /
• 2016

This paper presents a new high-efficient algorithm and architecture for an elliptic curve cryptographic processor. To reduce the computational complexity, novel modified Lopez-Dahab scalar point multiplication and left-to-right algorithms are proposed for point multiplication operation. Moreover, bit-serial Galois-field multiplication is used in order to decrease hardware complexity. The field multiplication operations are performed in parallel to improve system latency. As a result, our approach can reduce hardware costs, while the total time required for point multiplication is kept to a reasonable amount. The results on a Xilinx Virtex-5, Virtex-7 FPGAs and VLSI implementation show that the proposed architecture has less hardware complexity, number of clock cycles and higher efficiency than the previous works.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제7권3호
• /
• pp.600-612
• /
• 2013

In 2006, Zhang and Wang proposed a data hiding scheme based on Exploiting Modification Direction (EMD) to increase data hiding capacity. The major benefit of EMD is providing embedding capacity greater than 1 bit per pixel. Since then, many EMD-type data hiding schemes have been proposed. However, a serious disadvantage common to these approaches is that the embedded data is compromised when the embedding function is disclosed. Our proposed secure data hiding scheme remedies this disclosure shortcoming by employing an additional modulus function. The provided security analysis of our scheme demonstrates that attackers cannot get the secret information from the stegoimage even if the embedding function is made public. Furthermore, our proposed scheme also gives a simple solution to the overflow/underflow problem and maintains high embedding capacity and good stegoimage quality.

• 전자통신동향분석
• /
• 제17권6호통권78호
• /
• pp.146-154
• /
• 2002

본 고에서는 최근 IT-NT 융합 기술 중 각광받고 있는 양자 정보통신 기술의 기초 이론 및 최신 동향 그리고, 실제적인 시스템 구현을 위한 구성 요소들을 살펴보고자 한다. 양자정보통신 기술은 광자(光子)의 양자역학적 특성에 기반을 둔 기술로서 양자 이론과 밀접한 관련을 가진 기술 분야이다. 일반적으로 양자정보처리 기술은 크게 양자 컴퓨터(quantum computer)와 양자 암호화(quantum cryptography) 기술, 양자 통신(quantum communication) 등으로 구분된다. 양자정보통신의 각 분야 기술이 아직은 기초연구 수준에 있지만 세계적으로 그 중요성을 인식하고 대규모 투자를 아끼지 않는 분야이기 때문에, 이 분야에 대한 투자를 소홀히 하면 기술 종속 또는 기술 후진국으로 전락할 수도 있다. 그러므로, 본 고에서는 외국의 기술 발전 추세에 대처하고 자체적인 관련 기반 기술을 확보하기 위한 기초 이론과 기술 동향에 대해 간략히 살펴보기로 한다.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2006년도 하계종합학술대회
• /
• pp.321-322
• /
• 2006

In this paper, we propose a method that extracts invariant iris codes from user's iris pattern in order to apply these codes to a new cryptographic construct called fuzzy vault. The fuzzy vault, proposed by Juels and Sudan, has been used to manage cryptographic key safely by merging with biometrics. Generally, iris data has intra-variation of iris pattern according to sensed environmental changes, but cryptography requires correctness. Therefore, to combine iris data and fuzzy vault, we have to extract an invariant iris feature from iris pattern. In this paper, we obtain invariant iris codes by clustering iris features extracted by independent component analysis(ICA) transform. From experimental results, we proved that the iris codes extracted by our method are invariant to sensed environmental changes and can be used in fuzzy vault.