Expressive Policy Analysis with Enhanced System Dynamicity

Despite several research studies, the effective analysis of policy based systems remains a significant challenge. Policy analysis should at least (i) be expressive (ii) take account of obligations and authorizations, (iii) include a dynamic system model, and (iv) give useful diagnostic information. We present a logic-based policy analysis framework which satisfies these requirements, showing how many significant policy-related properties can be analysed, and we give details of a prototype implementation. Copyright 2009 ACM

Enhancing data privacy and security in Internet of Things through decentralized models and services

exploits a Byzantine Fault Tolerant (BFT) blockchain, in order to perform collaborative and dynamic botnet detection by collecting and auditing IoT devices’ network traffic flows as blockchain transactions. Secondly, we take the challenge to decentralize IoT, and design a hybrid blockchain architecture for IoT, by proposing Hybrid-IoT. In Hybrid-IoT, subgroups of IoT devices form PoW blockchains, referred to as PoW sub-blockchains. Connection among the PoW sub-blockchains employs a BFT inter-connector framework. We focus on the PoW sub-blockchains formation, guided by a set of guidelines based on a set of dimensions, metrics and bounds

A framework in support of emergency management for specified and unspecified emergencies.

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Quantifying Performance Costs of Database Fine-Grained Access Control

Fine-grained access control is a conceptual approach to addressing database security requirements. In relational database management systems, fine-grained access control refers to access restrictions enforced at the row, column, or cell level. While a number of commercial implementations of database fine-grained access control are available, there are presently no generalized approaches to implementing fine-grained access control for relational database management systems. Fine-grained access control is potentially a good solution for database professionals and system architects charged with designing database applications that implement granular security or privacy protection features. However, in the oral tradition of the database community, fine-grained access control is spoken of as imposing significant performance penalties, and is therefore best avoided. Regardless, there are current and emerging social, legal, and economic forces that mandate the need for efficient fine-grained access control in relational database management systems. In the study undertaken, the author was able to quantify the performance costs associated with four common implementations of fine-grained access control for relational database management systems. Security benchmarking was employed as the methodology to quantify performance costs. Synthetic data from the TPC-W benchmark as well as representative data from a real-world application were utilized in the benchmarking process. A simple graph-base performance model for Fine-grained Access Control Evaluation (FACE) was developed from benchmark data collected during the study. The FACE model is intended for use in predicting throughput and response times for relational database management systems that implement fine-grained access control using one of the common fine-grained access control mechanisms - authorization views, the Hippocratic Database, label-based access control, and transparent query rewrite. The author also addresses the issue of scalability for fine-grained access control mechanisms that were evaluated in the study

A simple and expressive semantic framework for policy composition in access control\r\n

In defining large, complex access control policies, one would like to compose sub-policies, perhaps authored by different organizations, into a single global policy. Existing policy composition approaches tend to be ad-hoc, and do not explain whether too many or too few policy combinators have been defined. We define an access controlpolicy as a four-valued predicate that maps accesses to either grant, deny, conflict, or unspecified. These correspond to the four elements of the Belnap bilattice. Functions on this bilattice are then extended to policies to serve as policy combinators. We argue that this approach provides a simple andnatural semantic framework for policy composition, with a minimal but functionally complete set of policy combinators. We define derived, higher-level operators that are convenient for the specification of access control policies, and enable the decoupling of conflict resolution from policy composition. Finally, we propose a basic query language and show that it can reduce important analyses (e.g., conflict analysis) to checks of policy refinement. Copyright 2007 ACM.Accepted versio