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1.
Private information retrieval(PIR) is an important privacy protection issue of secure multi-party computation, but the PIR protocols based on classical cryptography are vulnerable because of new technologies,such as quantum computing and cloud computing. The quantum private queries(QPQ) protocols available, however, has a high complexity and is inefficient in the face of large database. This paper, based on the QKD technology which is mature now, proposes a novel QPQ protocol utilizing the key dilution and auxiliary parameter. Only N quits are required to be sent in the quantum channel to generate the raw key, then the straight k bits in the raw key are added bitwise to dilute the raw key, and a final key is consequently obtained to encrypt the database. By flexible adjusting of auxiliary parameters θ and k, privacy is secured and the query success ratio is improved. Feasibility and performance analyses indicate that the protocol has a high success ratio in first-trial query and is easy to implement, and that the communication complexity of O(N) is achieved. 相似文献
2.
带关键字搜索的公钥加密(PEKS)是一种有用的加密原语,它允许用户将在加密数据上搜索的功能委托给不可信的第三方服务器,而不影响原始数据的安全性和隐私性。但是,由于缺乏对于数据的加密以及解密能力,PEKS方案不能单独进行使用,必须与标准的公钥加密方案(PKE)相结合。因此,Baek等人在2006年引入了一种新的加密原语,称为结合PKE和PEKS的加密方案(PKE+PEKS),它同时提供了PKE和PEKS的功能。目前,已有文献提出了几种PKE+PEKS方案。然而,他们都没有考虑关键字猜测攻击的问题。本文提出一个新的高效且能够抵抗关键字猜测攻击的PKE+PEKS方案,与已有方案相比,该方案在性能上有很大的提升,并且在生成关键字和数据密文时,不需要使用双线性对,极大地降低了计算和存储成本。安全性分析表明,本文中所提出的方案能够满足密文隐私安全性、陷门不可区分性和抗关键字猜测攻击的安全性。效率分析表明,本分提出的方案更加高效。 相似文献
3.
Mingchang Lin Yufei Zhang Guosong Chen Ming Jiang 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(45):6065-6070
Glyco‐mimicking nanoparticles (glyco‐NPs) with Förster resonance energy transfer (FRET) donor and acceptor groups formed via dynamic covalent bond of benzoboroxole and sugar from two complementary polymers are prepared. The glyco‐NPs are proved to be quite stable under physiological conditions but sensitive to pH. So the glyco‐NPs can be internalized by dendritic cells with integrity and nontoxicity and then dissociate within the acidic organelles. This particle dissociation is directly observed and visualized in vitro, for the first time via the FRET measurements and fluorescent microscopy. This feature makes controlled release of drug or protein by glyco‐NPs possible, i.e., when model antigen Ovalbumin is loaded in the glyco‐NPs, the released Ovalbumin in dendritic cells stimulates T cells more efficiently than the free Ovalbumin itself as a result of the enhanced antigen processing and presentation. Thus, the results enlighten a bright future of the glyco‐NPs in immunotherapy. 相似文献
4.
5.
This study addresses the problem of choosing the most suitable probabilistic model selection criterion for unsupervised learning
of visual context of a dynamic scene using mixture models. A rectified Bayesian Information Criterion (BICr) and a Completed
Likelihood Akaike’s Information Criterion (CL-AIC) are formulated to estimate the optimal model order (complexity) for a given
visual scene. Both criteria are designed to overcome poor model selection by existing popular criteria when the data sample
size varies from small to large and the true mixture distribution kernel functions differ from the assumed ones. Extensive
experiments on learning visual context for dynamic scene modelling are carried out to demonstrate the effectiveness of BICr
and CL-AIC, compared to that of existing popular model selection criteria including BIC, AIC and Integrated Completed Likelihood
(ICL). Our study suggests that for learning visual context using a mixture model, BICr is the most appropriate criterion given
sparse data, while CL-AIC should be chosen given moderate or large data sample sizes. 相似文献
6.
With the proliferation of mobile computing technologies, location based services have been identified as one of the most promising
target application. We classify mobile information service domains based on feature characteristics of the information sources
and different patterns of mobile information access. By carefully examining the service requirements, we identify the dynamic
data management problem that must be addressed for effective location based services in mobile environments. We then devise
a general architecture and cost model for servicing both location independent and location dependent data. Based on the architecture
and cost model, we propose a set of dynamic data management strategies that employs judicious caching, proactive server pushing
and neighborhood replication to reduce service cost and improve response time under changing user mobility and access patterns.
Detail behavior analysis helps us in precisely capturing when and how to apply these strategies. Simulation results suggest
that different strategies are effective for different types of data in response to different patterns of movement and information
access.
Shiow-yang Wu is an associate professor of the Department of Computer Science and Information Engineering at National Dong Hwa University,
Hualien, Taiwan, R.O.C. He received the BS and MS degrees in computer engineering from National Chiao Tung University, Hsinchu,
Taiwan, ROC, and the PhD degree in computer science from the University of Texas at Austin in 1984, 1986, and 1995, respectively.
His research interests include data/knowledge bases, mobile computing, distributed processing, intelligence information systems,
and electronic commerce.
Kun-Ta Wu was born in Taipei, Taiwan, R.O.C., in 1976. He received the B.S. degree in computer science from Soochow University, Taipei,
Taiwan, R.O.C., in 1999 and the M.S. degree in computer science and information engineering from National Dong Hwa University,
Hualien, Taiwan, R.O.C., in 2001.
Currently, he is an Assistant Researcher in the Domestic Division at Science and Technology Information Center, National Science
Council, R.O.C., as a member of Information Gathering and Analysis Group of National Information and Communication Security
Taskforce. His research interests include mobile computing, wireless network and information security. 相似文献
7.
燃气管网动态仿真的研究及应用 总被引:2,自引:0,他引:2
研究和了解燃气在管道中的流动,是进行燃气管网系统优化和提高管网输运系统安全性的前提和基础。以流体力学三大守恒方程为基础,建立了等温和非等温条件下的燃气管网稳态和动态仿真理论模型。以有限差分法为基础,得到了上述模型的求解方法,并加入了耗散项,提高了求解方法的稳定性。通过增加初始点和延长出口点的方法,简化了模型的求解。通过在北京六环天然气管网中的初步应用,分别得到了与实际值综合相对误差为1.21%和2.62%的压力和流量仿真值,从而验证了模型及求解方法的可靠性。 相似文献
8.
Aqueous solutions of poly(vinyl pyrrolidone)-fullerene complexes (PVP-C70) have been studied using static and dynamic light scattering methods. Two diffusive processes were detected. The slow diffusion was interpreted as dynamics of large intermolecular PVP-C70 complexes while the fast diffusion was associated with the presence of individual PVP molecules in solution. It was also shown that the molecular weights and dimensions of PVP-C70 complexes are smaller than for PVP-C60 by a factor of 2.5-3. In aqueous solutions of PVP-C70 complex the depolarization and dissymmetry of scattered light were observed in contrast to PVP-C60 solutions. It reveals the existence of anisotropic structures in PVP-C70 solutions. Intermolecular interactions within PVP-C70 complexes are weak and a hydrodynamic field can destroy complexes. 相似文献
9.
10.
PKI/CA技术综述 总被引:6,自引:0,他引:6
公开密钥基础设施(PKI)是解决网络安全的技术.典型PKI应用系统包括安全Web、注册机构(RA)、认证机构(CA)、目录(LDAP)和数据库等服务器.RA验证客户证书申请后提交CA.CA检查信息完整和数字签名正确后把证书存放到证书库和目录服务器,并将签发证书序列号通知客户和RA.客户即可使用该号通过目录服务器下载证书.1993年以来,美、加、欧洲、韩、日等国已相继展开PKI研究.我国2001年将PKI列入十五863计划,并着手解决PKI标准化、CA互联互通等关键技术问题。 相似文献