• Title/Summary/Keyword: SHA algorithm

검색결과 61건 처리시간 0.024초

High Capacity Information Hiding Method Based on Pixel-value Adjustment with Modulus Operation

  • Li, Teng;Zhang, Yu;Wang, Sha;Sun, Jun-jie
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제15권4호
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    • pp.1521-1537
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    • 2021
  • Through information hiding technique, secret message can be hidden in pictures. Stego-image quality and hiding capacity are two important metrics for information hiding. To enhance these metrics, many schemes were proposed by scholars in recent years. Some of them are effective and successful, but there is still a room for further improvement. A high capacity information hiding scheme (PAMO, Pixel-value Adjustment with Modulus Operation Algorithm) is introduced in this paper. PAMO scheme uses pixel value adjustment with modulus operation to hide confidential data in cover-image. PAMO scheme and some referenced schemes are implemented in Python and experiments are carried out to evaluate their performance. In the experiments, PAMO scheme shows better performance than other methods do. When secret message length is less than 72000 bits, the highest hiding capacity of PAMO can reach 7 bits per pixel, at the same time the PSNR of stego-images is greater than 30 dB.

Secure Data Sharing in The Cloud Through Enhanced RSA

  • Islam abdalla mohamed;Loay F. Hussein;Anis Ben Aissa;Tarak kallel
    • International Journal of Computer Science & Network Security
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    • 제23권2호
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    • pp.89-95
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    • 2023
  • Cloud computing today provides huge computational resources, storage capacity, and many kinds of data services. Data sharing in the cloud is the practice of exchanging files between various users via cloud technology. The main difficulty with file sharing in the public cloud is maintaining privacy and integrity through data encryption. To address this issue, this paper proposes an Enhanced RSA encryption schema (ERSA) for data sharing in the public cloud that protects privacy and strengthens data integrity. The data owners store their files in the cloud after encrypting the data using the ERSA which combines the RSA algorithm, XOR operation, and SHA-512. This approach can preserve the confidentiality and integrity of a file in any cloud system while data owners are authorized with their unique identities for data access. Furthermore, analysis and experimental results are presented to verify the efficiency and security of the proposed schema.

모션 속도와 다중 초기 중심점 예측에 기반한 빠른 비디오 모션 추정 알고리즘 (Fast Video Motion Estimation Algorithm Based on Motion Speed and Multiple Initial Center Points Prediction)

  • 팽소호;뮤잠멜;윤병춘;김덕환
    • 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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    • 제16권12호
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    • pp.1219-1223
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    • 2010
  • 본 논문은 모션 속도와 다수의 초기 중심점에 기반한 빠른 모션 추정 알고리즘을 제안한다. 제안한 방법은 시공간적 이웃 모션 벡터들에 의해 초기 탐색점을 예측한다. 모션벡터를 빠르게 구하기 위하여 모션 속도와 예측된 초기 중심점들에 기반한 동적인 탐색 패턴이 이용된다. 제안한 방법은 시공간 정보와 동적 탐색 패턴을 이용하여 탐색 속도를 매우 빠르게 할 뿐만 아니라 양질의 영상화질을 유지할 수 있다. 실험결과를 통해 제안한 방법이 완전 탐색, 새로운 삼단계 탐색, 사단계 탐색 방법들과 비교하여 검색시간을 줄이면서 PSNR 관점에서 양질의 영상화질을 제공함을 알 수 있다.

기밀성과 무결성이 우수한 SHACAL-2 기반 스트림 암호 설계 및 구현 (Design and Implementation of Stream Cipher based on SHACAL-2 Superior in the Confidentiality and Integrity)

  • 김길호;조경연
    • 한국멀티미디어학회논문지
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    • 제16권12호
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    • pp.1427-1438
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    • 2013
  • 5단계 파이프라인으로 구성된 기밀성과 무결성이 우수하고 실시간처리가 가능한 128비트 출력 스트림 암호를 개발했다. 개발한 스트림 암호는 ASR 277비트와 SHACAL-2를 통해 128비트 스트림을 만들고 이를 CFB모드 적용한 후 표백처리 과정을 통하여 최종적인 128비트 암호문을 만드는 스트림 암호 알고리즘이다. 스트림 암호의 하드웨어는 Verilog HDL을 사용하여 Modelsim 6.5d를 활용하여 기능을 검증하였고, 성능은 Quartus II 12.0을 활용하여 분석했고, Worst Case에서 Max Frequency는 33.34MHz(4.27Gbps)의 빠른 성능을 보여주었다. 이는 무선 인터넷과 센서 네트워크 및 DRM 환경의 속도를 충분히 만족함을 보여준다. 기밀성과 무결성이 우수한 스트림 암호 알고리즘 개발에 본 논문은 매우 유용한 아이디어를 제공하고 있다.

The compression-shear properties of small-size seismic isolation rubber bearings for bridges

  • Wu, Yi-feng;Wang, Hao;Sha, Ben;Zhang, Rui-jun;Li, Ai-qun
    • Structural Monitoring and Maintenance
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    • 제5권1호
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    • pp.39-50
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    • 2018
  • Taking three types of bridge bearings with diameter being 100 mm as examples, the theoretical analysis, the experimental research as well as the numerical simulation of these bearings is conducted. Since the normal compression and shear machines cannot be applied to the small-size bearings, an improved equipment to test the properties of these bearings is proposed and fabricated. Besides, the simulation of the bearings is conducted based on the explicit finite element software ANSYS/LS-DYNA, and some parameters of the bearings are modified in the finite element model to reduce the computation cost effectively. Results show that all the research methods are capable of revealing the fundamental properties of the small-size bearings, and a combined use of these methods can better catch both the integral properties and the inner detailed mechanical behaviors of the bearings.

Invariant-Feature Based Object Tracking Using Discrete Dynamic Swarm Optimization

  • Kang, Kyuchang;Bae, Changseok;Moon, Jinyoung;Park, Jongyoul;Chung, Yuk Ying;Sha, Feng;Zhao, Ximeng
    • ETRI Journal
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    • 제39권2호
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    • pp.151-162
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    • 2017
  • With the remarkable growth in rich media in recent years, people are increasingly exposed to visual information from the environment. Visual information continues to play a vital role in rich media because people's real interests lie in dynamic information. This paper proposes a novel discrete dynamic swarm optimization (DDSO) algorithm for video object tracking using invariant features. The proposed approach is designed to track objects more robustly than other traditional algorithms in terms of illumination changes, background noise, and occlusions. DDSO is integrated with a matching procedure to eliminate inappropriate feature points geographically. The proposed novel fitness function can aid in excluding the influence of some noisy mismatched feature points. The test results showed that our approach can overcome changes in illumination, background noise, and occlusions more effectively than other traditional methods, including color-tracking and invariant feature-tracking methods.

Integrated Optimization Design of Carbon Fiber Composite Framework for Small Lightweight Space Camera

  • Yang, Shuai;Sha, Wei;Chen, Changzheng;Zhang, Xingxiang;Ren, Jianyue
    • Journal of the Optical Society of Korea
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    • 제20권3호
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    • pp.389-395
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    • 2016
  • A Carbon Fiber Composite (CFC) framework was designed for a small lightweight space camera. According to the distribution characteristics of each optical element in the optical system, CFC (M40J) was chosen to accomplish the design of the framework. TC4 embedded parts were used to solve the low accuracy of the CFC framework interface problem. An integrated optimization method and the optimization strategy which combined a genetic global optimization algorithm with a downhill simplex local optimization algorithm were adopted to optimize the structure parameters of the framework. After optimization, the total weight of the CFC framework and the TC4 embedded parts is 15.6 kg, accounting for only 18.4% that of the camera. The first order frequency of the camera reaches 104.8 Hz. Finally, a mechanical environment test was performed, and the result demonstrates that the first order frequency of the camera is 102 Hz, which is consistent with the simulation result. It further verifies the rationality and correctness of the optimization result. The integrated optimization method mentioned in this paper can be applied to the structure design of other space cameras, which can greatly improve the structure design efficiency.

하드웨어 공유와 캐리 보존 덧셈을 이용한 MDS 해쉬 프로세서의 설계 (Design of MD5 Hash Processor with Hardware Sharing and Carry Save Addition Scheme)

  • 최병윤;박영수
    • 정보보호학회논문지
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    • 제13권4호
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    • pp.139-149
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    • 2003
  • 본 논문에서는 하드웨어 공유와 캐리 보존 덧셈 연산을 이용하여 MD5 알고리즘을 구현하는 면적 효율적인 해쉬 프로세서를 하드웨어로 설계하였다. 면적을 최소화하기 위해, MD5의 1 단계 동작을 2개의 부분 단계로 세분화하고, 각각의 부분 단계 동작을 동일 하드웨어로 구현하는 방식으로 하드웨어 공유를 극대화하였다. 그리고 MD5의 부분 단계를 구성하는 3개의 직렬 캐리 전달 덧셈 동작을 2개의 캐리 보존 덧셈과 1개의 캐리 전달 덧셈으로 변환하여 동작 주파수를 증가시켰다. MD5 해쉬 프로세서는 0.25$\mu\textrm{m}$ CMOS 표준 셀 라이브러리로 합성한 결과 약 13,000개의 게이트 수로 구성되며, 타이밍 분석 결과 설계된 MD5 해쉬 프로세서는 120 MHz의 동작 주파수에서 512 비트 입력 메시지에 대해 465 Mbps의 성능을 갖는다.

Noncontrast Computed Tomography-Based Radiomics Analysis in Discriminating Early Hematoma Expansion after Spontaneous Intracerebral Hemorrhage

  • Zuhua Song;Dajing Guo;Zhuoyue Tang;Huan Liu;Xin Li;Sha Luo;Xueying Yao;Wenlong Song;Junjie Song;Zhiming Zhou
    • Korean Journal of Radiology
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    • 제22권3호
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    • pp.415-424
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    • 2021
  • Objective: To determine whether noncontrast computed tomography (NCCT) models based on multivariable, radiomics features, and machine learning (ML) algorithms could further improve the discrimination of early hematoma expansion (HE) in patients with spontaneous intracerebral hemorrhage (sICH). Materials and Methods: We retrospectively reviewed 261 patients with sICH who underwent initial NCCT within 6 hours of ictus and follow-up CT within 24 hours after initial NCCT, between April 2011 and March 2019. The clinical characteristics, imaging signs and radiomics features extracted from the initial NCCT images were used to construct models to discriminate early HE. A clinical-radiologic model was constructed using a multivariate logistic regression (LR) analysis. Radiomics models, a radiomics-radiologic model, and a combined model were constructed in the training cohort (n = 182) and independently verified in the validation cohort (n = 79). Receiver operating characteristic analysis and the area under the curve (AUC) were used to evaluate the discriminative power. Results: The AUC of the clinical-radiologic model for discriminating early HE was 0.766. The AUCs of the radiomics model for discriminating early HE built using the LR algorithm in the training and validation cohorts were 0.926 and 0.850, respectively. The AUCs of the radiomics-radiologic model in the training and validation cohorts were 0.946 and 0.867, respectively. The AUCs of the combined model in the training and validation cohorts were 0.960 and 0.867, respectively. Conclusion: NCCT models based on multivariable, radiomics features and ML algorithm could improve the discrimination of early HE. The combined model was the best recommended model to identify sICH patients at risk of early HE.

UTrustDisk: An Efficient Data Protection Scheme for Building Trusted USB Flash Disk

  • Cheng, Yong;Ma, Jun;Ren, Jiangchun;Mei, Songzhu;Wang, Zhiying
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제11권4호
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    • pp.2276-2291
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    • 2017
  • Data protection of removable storage devices is an important issue in information security. Unfortunately, most existing data protection mechanisms are aimed at protecting computer platform which is not suitable for ultra-low-power devices. To protect the flash disk appropriately and efficiently, we propose a trust based USB flash disk, named UTrustDisk. The data protection technologies in UTrustDisk include data authentication protocol, data confidentiality protection and data leakage prevention. Usually, the data integrity protection scheme is the bottleneck in the whole system and we accelerate it by WH universal hash function and speculative caching. The speculative caching will cache the potential hot chunks for reducing the memory bandwidth pollution. We adopt the symmetric encryption algorithm to protect data confidentiality. Before mounting the UTrustDisk, we will run a trusted virtual domain based lightweight virtual machine for preventing information leakage. Besides, we prove formally that UTrustDisk can prevent sensitive data from leaking out. Experimental results show that our scheme's average writing throughput is 44.8% higher than that of NH scheme, and 316% higher than that of SHA-1 scheme. And the success rate of speculative caching mechanism is up to 94.5% since the access pattern is usually sequential.