Biblio

Risk-based authentication (RBA) extends authentication mechanisms to make them more robust against account takeover attacks, such as those using stolen passwords. RBA is recommended by NIST and NCSC to strengthen password-based authentication, and is already used by major online services. Also, users consider RBA to be more usable than two-factor authentication and just as secure. However, users currently obtain RBA’s high security and usability benefits at the cost of exposing potentially sensitive personal data (e.g., IP address or browser information). This conflicts with user privacy and requires to consider user rights regarding the processing of personal data. We outline potential privacy challenges regarding different attacker models and propose improvements to balance privacy in RBA systems. To estimate the properties of the privacy-preserving RBA enhancements in practical environments, we evaluated a subset of them with long-term data from 780 users of a real-world online service. Our results show the potential to increase privacy in RBA solutions. However, it is limited to certain parameters that should guide RBA design to protect privacy. We outline research directions that need to be considered to achieve a widespread adoption of privacy preserving RBA with high user acceptance.

Tensors, as the multidimensional generalization of matrices, are naturally suited for representing and processing high-dimensional data. To date, tensors have been widely adopted in various data-intensive applications, such as machine learning and big data analysis. However, due to the inherent large-size characteristics of tensors, tensor algorithms, as the approaches that synthesize, transform or decompose tensors, are very computation and storage expensive, thereby hindering the potential further adoptions of tensors in many application scenarios, especially on the resource-constrained hardware platforms. In this paper, we propose a reduced-complexity SVD (Singular Vector Decomposition) scheme, which serves as the key operation in Tucker decomposition. By using iterative self-multiplication, the proposed scheme can significantly reduce the storage and computational costs of SVD, thereby reducing the complexity of the overall process. Then, corresponding hardware architecture is developed with 28nm CMOS technology. Our synthesized design can achieve 102GOPS with 1.09 mm2 area and 37.6 mW power consumption, and thereby providing a promising solution for accelerating Tucker decomposition.

In the globalized knowledge economy, big data analytics have been widely applied in diverse areas. A critical issue in big data analysis on personal information is the possible leak of personal privacy. Therefore, it is necessary to have an anonymization-based de-identification method to avoid undesirable privacy leak. Such method can prevent published data form being traced back to personal privacy. Prior empirical researches have provided approaches to reduce privacy leak risk, e.g. Maximum Distance to Average Vector (MDAV), Condensation Approach and Differential Privacy. However, previous methods inevitably generate synthetic data of different sizes and is thus unsuitable for general use. To satisfy the need of general use, k-anonymity can be chosen as a privacy protection mechanism in the de-identification process to ensure the data not to be distorted, because k-anonymity is strong in both protecting privacy and preserving data authenticity. Accordingly, this study proposes an optimized multidimensional method for anonymizing data based on both the priority weight-adjusted method and the mean difference recommending tree method (MDR tree method). The results of this study reveal that this new method generate more reliable anonymous data and reduce the information loss rate.

In the globalized knowledge economy, big data analytics have been widely applied in diverse areas. A critical issue in big data analysis on personal information is the possible leak of personal privacy. Therefore, it is necessary to have an anonymization-based de-identification method to avoid undesirable privacy leak. Such method can prevent published data form being traced back to personal privacy. Prior empirical researches have provided approaches to reduce privacy leak risk, e.g. Maximum Distance to Average Vector (MDAV), Condensation Approach and Differential Privacy. However, previous methods inevitably generate synthetic data of different sizes and is thus unsuitable for general use. To satisfy the need of general use, k-anonymity can be chosen as a privacy protection mechanism in the de-identification process to ensure the data not to be distorted, because k-anonymity is strong in both protecting privacy and preserving data authenticity. Accordingly, this study proposes an optimized multidimensional method for anonymizing data based on both the priority weight-adjusted method and the mean difference recommending tree method (MDR tree method). The results of this study reveal that this new method generate more reliable anonymous data and reduce the information loss rate.

In the process of big data analysis and processing, a key concern blocking users from storing and processing their data in the cloud is their misgivings about the security and performance of cloud services. There is an urgent need to develop an approach that can help each cloud service provider (CSP) to demonstrate that their infrastructure and service behavior can meet the users' expectations. However, most of the prior research work focused on validating the process compliance of cloud service without an accurate description of the basic service behaviors, and could not measure the security capability. In this paper, we propose a novel approach to verify cloud service security conformance called CloudSec, which reduces the description gap between the cloud provider and customer through modeling cloud service behaviors (CloudBeh Model) and security SLA (SecSLA Model). These models enable a systematic integration of security constraints and service behavior into cloud while using UPPAAL to check the conformance, which can not only check CloudBeh performance metrics conformance, but also verify whether the security constraints meet the SecSLA. The proposed approach is validated through case study and experiments with a cloud storage service based on OpenStack, which illustrates CloudSec approach effectiveness and can be applied in real cloud scenarios.

Power network is important part of national comprehensive energy resources transmission system in the way of energy security promise and the economy society running. Meanwhile, because of many industries involved, the development of grid can push national innovation ability. Nowadays, it makes the inner of smart grid flourish that material science, computer technique and information and communication technology go forward. This paper researches the function and modality of smart grid on energy, geography and technology dimensions. The analysis on the technology dimension is addressed on two aspects which are network control and interaction with customer. The mapping relationship between functions fo smart grid and eight key technologies, which are Large-capacity flexible transmission technology, DC power distribution technology, Distributed power generation technology, Large-scale energy storage technology, Real-time tracking simulation technology, Intelligent electricity application technology, The big data analysis and cloud computing technology, Wide-area situational awareness technology, is given. The research emphasis of the key technologies is proposed.
 

Data is one of the most valuable assets for organization. It can facilitate users or organizations to meet their diverse goals, ranging from scientific advances to business intelligence. Due to the tremendous growth of data, the notion of big data has certainly gained momentum in recent years. Cloud computing is a key technology for storing, managing and analyzing big data. However, such large, complex, and growing data, typically collected from various data sources, such as sensors and social media, can often contain personally identifiable information (PII) and thus the organizations collecting the big data may want to protect their outsourced data from the cloud. In this paper, we survey our research towards development of efficient and effective privacy-enhancing (PE) techniques for management and analysis of big data in cloud computing.We propose our initial approaches to address two important PE applications: (i) privacy-preserving data management and (ii) privacy-preserving data analysis under the cloud environment. Additionally, we point out research issues that still need to be addressed to develop comprehensive solutions to the problem of effective and efficient privacy-preserving use of data.