• 정보보호학회논문지
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• 제25권1호
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• pp.39-48
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• 2015

최근 개인정보보호에 관심이 증대되면서 암호화 솔루션 사용이 증가하고 있다. 또한, Windows XP 서비스 지원 종료와 함께 사용자의 운영체제 사양이 향상되면서, Bitlocker와 같은 Full Disk Encryption 솔루션의 활용도가 높아질 것으로 예상된다. 따라서 앞으로의 디지털 포렌식 조사는 Full Disk Encryption 환경에 대한 대응이 필요하다. 본 논문에서는 Full Disk Encryption 환경에 대응하는 디지털 증거 수집 절차를 제안하고 Full Disk Encryption 솔루션 중 사용률이 높은 제품들의 대응 방법 및 탐지 도구를 소개한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권12호
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• pp.5058-5072
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• 2015

Quaternions have been commonly employed in color image processing, but when the existing pure quaternion representation for color images is used in perceptual hashing, it would degrade the robustness performance since it is sensitive to image manipulations. To improve the robustness in color image perceptual hashing, in this paper a full quaternion representation for color images is proposed by introducing the local image luminance variances. Based on this new representation, a novel Full Quaternion Discrete Cosine Transform (FQDCT)-based hashing is proposed, in which the Quaternion Discrete Cosine Transform (QDCT) is applied to the pseudo-randomly selected regions of the novel full quaternion image to construct two feature matrices. A new hash value in binary is generated from these two matrices. Our experimental results have validated the robustness improvement brought by the proposed full quaternion representation and demonstrated that better performance can be achieved in the proposed FQDCT-based hashing than that in other notable quaternion-based hashing schemes in terms of robustness and discriminability.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권2호
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• pp.428-439
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• 2011

The main challenge in building efficient broadcast systems is to encrypt messages with short ciphertexts. In this paper, we present a new construction based on the identity. Our construction contains the desirable features, such as constant size ciphertexts and private keys, short public keys and not fixing the total number of possible users in the setup. In addition, the proposed scheme achieves the full security which is stronger than the selective-identity security. Furthermore we show that the proof of security does not rely on the random oracles. To the best our knowledge, it is the first efficient scheme that is full security and achieves constant size ciphertexts and private keys which solve the trade-off between the ciphertext size and the private key size.

• 정보보호학회논문지
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• 제18권4호
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• pp.27-35
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• 2008

본 논문에서는 블록 암호 SCO-1[12]에 대한 연관키 차분 공격을 소개한다. 본 논문에서 소개하는 공격은 SCO-1에 대한 첫 번째 공격이며 $2^{61}$개의 연관키 선택 암호문을 이용하여 $2^{120.59}$의 SCO-1 복호화 연산을 수행하여 SCO-1의 128-비트 비밀키를 복구한다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2015년도 춘계학술대회
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• pp.315-318
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• 2015

전 세계적으로 해운물류 안전 보안체계가 강화됨에 따라 국가물류보안 체계 구축을 위한 해운물류안전 보안 핵심기술 개발이 이루어지고 있다. 이러한 국제적 정서에 발맞추어, 국내에서도 감마선 핵종을 검출할 수 있는 휴대용 방사능 검출 장치에 대한 관심이 높아지고 있다. 본 논문에서는 휴대용 방사능 검출기의 Full-digital System을 제안하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권4호
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• pp.1941-1960
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• 2019

Unmanned aerial vehicles (UAVs), acting as mobile base stations (BSs), can be deployed in the typical fifth-generation mobile communications (5G) scenarios for the purpose of substantially enhancing the radio coverage. Meanwhile, UAV aided underlay device-to-device (D2D) communication mode can be activated for further improving the capacity of the 5G networks. However, this UAV aided D2D communication system is more vulnerable to eavesdropping attacks, resulting in security risks. In this paper, the D2D receivers work in full-duplex (FD) mode, which improves the security of the network by enabling these legitimate users to receive their useful information and transmit jamming signal to the eavesdropper simultaneously (with the same frequency band). The security communication under the UAV coverage is evaluated, showing that the system's (security) capacity can be substantially improved by taking advantage of the flexible radio coverage of UAVs. Furthermore, the closed-form expressions for the coverage probabilities are derived, showing that the cellular users (CUs)' secure coverage probability in downlink transmission is mainly impacted by the following three factors: its communication area, the relative position with UAV, and its eavesdroppers. In addition, it is observed that the D2D users or DUs' secure coverage probability is relevant to state of the UAV. The system's secure capacity can be substantially improved by adaptively changing the UAV's position as well as coverage.

• International Journal of Computer Science & Network Security
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• 제24권10호
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• pp.191-196
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• 2024

This paper presents a subfamily of quasi-orthogonal space time block codes (QOSTBC), named Exclusive Conjugate (ECQOSTBC), with full rate, full diversity and simple decoding at the receiver. Our approach estimates feedback constants at the receiver and the transmitter in turn modifies the transmitted symbols based on the estimated constants. This approach is an alternative method to those used in the literature to overcome the challenge of no existing STBC with full diversity and full rate with simple decoding for more than two transmitted antennas. Our simulation results show that the proposed family has better performance in terms of BER-SNR when compared to other codes presented in the literature. Finally, the estimated feedback constants in this work consists of only two real constants.

• International Journal of Computer Science & Network Security
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• 제22권6호
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• pp.241-245
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• 2022

The main purpose of the study is to determine the main factors influencing the economic environment of the region and its financial and economic security. Ukraine aspires to become a full member of the European Union, but the events of 2022 have changed everything. Full-scale military operations on the territory of Ukraine significantly affect its socio-economic situation Today, the issue of studying the negative impact of military operations on the economic environment is very relevant. Based on the results of the study, we have identified the main negative factors of the military impact on the economic environment of the region and its financial and economic security.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권2호
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• pp.562-576
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• 2020

The power allocation optimization problem is investigated for improving the physical-layer security in two-way relaying networks, where a full-duplex relay based half-jamming protocol (HJP-FDR) is considered. Specially, by introducing a power splitter factor, HJP-FDR divides the relay's power into two parts: one for forwarding the sources' signals, the other for jamming. An optimization problem for power split factor is first developed, which is proved to be concave and closed-form solution is achieved. Moreover, we formulate a power allocation problem to determine the sources' power subject to the total power constraint. Applying the achieved closed-form solutions to the above-mentioned problems, a two-stage strategy is proposed to implement the overall power allocation. Simulation results highlight the effectiveness of our proposed algorithm and indicate the necessity of optimal power allocation.

• 정보보호학회논문지
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• 제30권6호
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• pp.975-980
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• 2020

무선 센서 네트워크 보호를 위해 다양한 키 분배 및 관리 기법들이 제안되었지만 대부분 2차원(2D) 환경만을 고려한 시뮬레이션 및 성능 실험을 수행하였다. 본 논문에서는 실제 환경 3차원(3D) 지형적 특성이 키 사전 분배 기법에 미치는 영향을 알아보기 위해 Full Pairwise (FP) 기법, Random Pairwise (RP) 기법, 두 가지를 결합한 Full and Random Pairwise (FRP) 기법의 성능을 2D 환경과 3D 환경에서 비교분석한다. 실험을 위해 Blender와 Unity 등의 3차원 그래픽 툴과 네트워크 시뮬레이터인 NS-3를 활용한다. 결과적으로, 실제 3차원 지형에 따라 각 기법의 성능에 차이가 있음을 확인하였으며 배치 오류를 고려한 위치 기반 분배 기법인 FRP가 여러 측면에서 가장 효율성이 높음을 확인하였다.