scholarly journals An Efficient Tate Pairing Algorithm for a Decentralized Key-Policy Attribute Based Encryption Scheme in Cloud Environments

Cryptography ◽  
2018 ◽  
Vol 2 (3) ◽  
pp. 14
Author(s):  
Balaji Chandrasekaran ◽  
Ramadoss Balakrishnan

Attribute-based encryption (ABE) is used for achieving data confidentiality and access control in cloud environments. Most often ABE schemes are constructed using bilinear pairing which has a higher computational complexity, making algorithms inefficient to some extent. The motivation of this paper is on achieving user privacy during the interaction with attribute authorities by improving the efficiency of ABE schemes in terms of computational complexity. As a result the aim of this paper is two-fold; firstly, to propose an efficient Tate pairing algorithm based on multi-base number representation system using point halving (TP-MBNR-PH) with bases 1/2, 3, and 5 to reduce the cost of bilinear pairing operations and, secondly, the TP-MBNR-PH algorithm is applied in decentralized KP-ABE to compare its computational costs for encryption and decryption with existing schemes.

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Changji Wang ◽  
Jianfa Luo

There is an acceleration of adoption of cloud computing among enterprises. However, moving the infrastructure and sensitive data from trusted domain of the data owner to public cloud will pose severe security and privacy risks. Attribute-based encryption (ABE) is a new cryptographic primitive which provides a promising tool for addressing the problem of secure and fine-grained data sharing and decentralized access control. Key-policy attribute-based encryption (KP-ABE) is an important type of ABE, which enables senders to encrypt messages under a set of attributes and private keys are associated with access structures that specify which ciphertexts the key holder will be allowed to decrypt. In most existing KP-ABE scheme, the ciphertext size grows linearly with the number of attributes embedded in ciphertext. In this paper, we propose a new KP-ABE construction with constant ciphertext size. In our construction, the access policy can be expressed as any monotone access structure. Meanwhile, the ciphertext size is independent of the number of ciphertext attributes, and the number of bilinear pairing evaluations is reduced to a constant. We prove that our scheme is semantically secure in the selective-set model based on the general Diffie-Hellman exponent assumption.


Cloud security is becoming more essential than ever with the tremendous development of delicate cloud data. The cloud information and services are located in massively scalable data centers and can be accessed anywhere. Unfortunately, the development of cloud users has been followed by an increase in cloud malicious activity. More and more vulnerabilities are being found, and fresh safety advisories are being released almost every day. Millions of customers surf the cloud for different reasons, so they need extremely secure and persistent services. The cloud storage system interconnect with the a load of potential security risks. So the cross encryption of Ciphertext Policy Attribute Based Encryption (CPAB) and Key Policy Attribute-based encryption algorithm which increases the security level in the encryption side. A segmentation part helps in splitting the encrypted file in storing the data in the cloud side, the Desegmentation part in the receiver side can easily combines spitted data into the single file for validation examine an authentication level in the received data. Here the cloud storage easily with the file fragmentation processes. This processes research over the storing mass amount of data on off- site installation, which can eliminate the cost in maintaining the physical hardware. Cloud's future includes a much greater degree of privacy and authentication, particularly in extending the variety of apps. We suggest a straightforward data protection model where data is encrypted before it is introduced in the cloud using key policy attribute-based encryption to ensure data confidentiality and safety. The storing data is the most common application for the cloud server.


2021 ◽  
Vol 11 (15) ◽  
pp. 7007
Author(s):  
Janusz P. Paplinski ◽  
Aleksandr Cariow

This article presents an efficient algorithm for computing a 10-point DFT. The proposed algorithm reduces the number of multiplications at the cost of a slight increase in the number of additions in comparison with the known algorithms. Using a 10-point DFT for harmonic power system analysis can improve accuracy and reduce errors caused by spectral leakage. This paper compares the computational complexity for an L×10M-point DFT with a 2M-point DFT.


2012 ◽  
Vol 239-240 ◽  
pp. 1522-1527
Author(s):  
Wen Bo Wu ◽  
Yu Fu Jia ◽  
Hong Xing Sun

The bottleneck assignment (BA) and the generalized assignment (GA) problems and their exact solutions are explored in this paper. Firstly, a determinant elimination (DE) method is proposed based on the discussion of the time and space complexity of the enumeration method for both BA and GA problems. The optimization algorithm to the pre-assignment problem is then discussed and the adjusting and transformation to the cost matrix is adopted to reduce the computational complexity of the DE method. Finally, a synthesis method for both BA and GA problems is presented. The numerical experiments are carried out and the results indicate that the proposed method is feasible and of high efficiency.


2019 ◽  
Vol 470 ◽  
pp. 175-188 ◽  
Author(s):  
Jiguo Li ◽  
Qihong Yu ◽  
Yichen Zhang ◽  
Jian Shen

BMJ Open ◽  
2018 ◽  
Vol 8 (2) ◽  
pp. e015561 ◽  
Author(s):  
Samuel I Watson ◽  
Yen-Fu Chen ◽  
Julian F Bion ◽  
Cassie P Aldridge ◽  
Alan Girling ◽  
...  

IntroductionThis protocol concerns the evaluation of increased specialist staffing at weekends in hospitals in England. Seven-day health services are a key policy for the UK government and other health systems trying to improve use of infrastructure and resources. A particular motivation for the 7-day policy has been the observed increase in the risk of death associated with weekend admission, which has been attributed to fewer hospital specialists being available at weekends. However, the causes of the weekend effect have not been adequately characterised; many of the excess deaths associated with the ‘weekend effect’ may not be preventable, and the presumed benefits of improved specialist cover might be offset by the cost of implementation.Methods/designThe Bayesian-founded method we propose will consist of four major steps. First, the development of a qualitative causal model. Specialist presence can affect multiple, interacting causal processes. One or more models will be developed from the results of an expert elicitation workshop and probabilities elicited for each model and relevant model parameters. Second, systematic review of the literature. The model from the first step will provide search limits for a review to identify relevant studies. Third, a statistical model for the effects of specialist presence on care quality and patient outcomes. Fourth, valuation of outcomes. The expected net benefits of different levels of specialist intensity will then be evaluated with respect to the posterior distributions of the parameters.Ethics and disseminationThe study was approved by the Review Subcommittee of the South West Wales REC on 11 November 2013. Informed consent was not required for accessing anonymised patient case records from which patient identifiers had been removed. The findings of this study will be published in peer-reviewed journals; the outputs from this research will also form part of the project report to the HS&DR Programme Board.


2013 ◽  
Vol 2013 ◽  
pp. 1-8
Author(s):  
Konstantinos Koufos ◽  
Riku Jäntti

The key bottleneck for secondary spectrum usage is the aggregate interference to the primary system receivers due to simultaneous secondary transmissions. Existing power allocation algorithms for multiple secondary transmitters in the TV white space either fail to protect the TV service in all cases or they allocate extremely low power levels to some of the transmitters. In this paper, we propose a power allocation algorithm that favors equally the secondary transmitters and it is able to protect the TV service in all cases. When the number of secondary transmitters is high, the computational complexity of the proposed algorithm becomes high too. We show how the algorithm could be modified to reduce its computational complexity at the cost of negligible performance loss. The modified algorithm could permit a spectrum allocation database to allocate near optimal transmit power levels to tens of thousands of secondary transmitters in real time. In addition, we describe how the modified algorithm could be applied to allow decentralized power allocation for mobile secondary transmitters. In that case, the proposed algorithm outperforms the existing algorithms because it allows reducing the communication signalling overhead between mobile secondary transmitters and the spectrum allocation database.


2021 ◽  
Vol 1 (1) ◽  
pp. 32-50
Author(s):  
Nan Wang ◽  
Sid Chi-Kin Chau ◽  
Yue Zhou

Energy storage provides an effective way of shifting temporal energy demands and supplies, which enables significant cost reduction under time-of-use energy pricing plans. Despite its promising benefits, the cost of present energy storage remains expensive, presenting a major obstacle to practical deployment. A more viable solution to improve the cost-effectiveness is by sharing energy storage, such as community sharing, cloud energy storage and peer-to-peer sharing. However, revealing private energy demand data to an external energy storage operator may compromise user privacy, and is susceptible to data misuses and breaches. In this paper, we explore a novel approach to support energy storage sharing with privacy protection, based on privacy-preserving blockchain and secure multi-party computation. We present an integrated solution to enable privacy-preserving energy storage sharing, such that energy storage service scheduling and cost-sharing can be attained without the knowledge of individual users' demands. It also supports auditing and verification by the grid operator via blockchain. Furthermore, our privacy-preserving solution can safeguard against a majority of dishonest users, who may collude in cheating, without requiring a trusted third-party. We implemented our solution as a smart contract on real-world Ethereum blockchain platform, and provided empirical evaluation in this paper 1 .


Author(s):  
Ya. V. Kryukov ◽  
◽  
D. A. Pokamestov ◽  
E. V. Rogozhnikov ◽  
S. A. Novichkov ◽  
...  

Currently, an active deployment of radio access networks for mobile communication systems 5G New Radio is being observed. The architecture of networks is developing rapidly, where significant part of the functions is performed in a virtual cloud space of a personal computer. The computing power of a personal computer must be sufficient to execute network protocols in real time. To reduce the cost of deploying 5G NR networks, the configuration of each remote computer must be optimally matched to the scale of a particular network. Therefore, an urgent direction of research is the assessment of the execution time of the 5G NR protocol stack on various configurations of computers and the development of a mathematical model for data analysis, approximation of dependencies and making recommendations. In this paper, the authors provide an overview of the main 5G NR network architectures, as well as a description of the methods and tools that can be used to estimate the computational complexity of the 5G NR protocol stack. The final section provides an analysis of the computational complexity of the protocol stack, obtained during the experiments by colleagues in partner institutions.


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