Authorization Research Papers - Academia.edu (original) (raw)

The typed access matrix (TAM) model is defined by introducing the notion of strong typing into the Harrison, Ruzzo, and Ullman model (HRU) (M. H. Harrison et al., 1978). It is shown that monotonic TAM (MTAM) has decidable, but NP-hard,... more

The typed access matrix (TAM) model is defined by introducing the notion of strong typing into the Harrison, Ruzzo, and Ullman model (HRU) (M. H. Harrison et al., 1978). It is shown that monotonic TAM (MTAM) has decidable, but NP-hard, safety for its acyclic creation cases. It is further shown that ternary MTAM has polynomial time safety analysis for its acyclic cases, even though it is, in general, equivalent to MTAM. Ternary MTAM thus has strong safety properties. The expressive power of ternary MTAM has been shown to be equivalent to MTAM in general. The results establish that strong typing is crucial to achieving a useful demarcation between decidable and undecidable safety, and ternary monotonic commands are critical for tractable safety analysis

In open systems like the Internet, traditional approaches to security based on identity do not provide a solution to the problem of establishing trust between strangers, because strangers do not share the same security domain. A new... more

In open systems like the Internet, traditional approaches to security based on identity do not provide a solution to the problem of establishing trust between strangers, because strangers do not share the same security domain. A new approach to establishing trust between strangers is trust negotiation, the bilateral exchange of digital credentials describing attributes of the negotiation participants. This approach relies on access control policies that govern access to protected resources by specifying credential combinations that must be submitted to obtain authorization. We describe a model for trust negotiation, focusing on the central role of policies. We delineate requirements for policy languages and runtime systems for trust negotiation, and evaluate four existing policy languages for trust management with respect to those requirements. We conclude with recommendations for extending existing policy languages or developing new policy languages to make them suitable for use in future trust negotiation systems.

— The smart grid, as the next generation of the power grid, is characterized by employing many different types of intelligent devices, such as intelligent electronic devices located at substations, smart meters positioned in the home area... more

— The smart grid, as the next generation of the power grid, is characterized by employing many different types of intelligent devices, such as intelligent electronic devices located at substations, smart meters positioned in the home area network, and outdoor field equipment deployed in the fields. In addition, there are various users in the smart grid network, including customers, operators, maintenance personnel, and so on, who use these devices for various purposes. Therefore, a secure and efficient mutual authentication and authorization scheme is needed in the smart grid to prevent various insider and outsider attacks on many different devices. In this paper, we propose an authentication and authorization scheme for mitigating outsider and insider threats in the smart grid by verifying the user authorization and performing the user authentication together whenever a user accesses the devices. The proposed scheme computes each user role dynamically using an attribute-based access control and verifies the identity of the user together with the device. Security and performance analysis show that the proposed scheme resists various insider as well as outsider attacks, and is more efficient in terms of communication and computation costs in comparison with the existing schemes. The correctness of the proposed scheme is also proved using BAN-Logic and Proverif.

Authorization, authentication, and accounting schemes for WiMAX (Worldwide Interoperability for Microwave Access) are the focus of this paper. WiMAX works as a wireless metropolitan area network (MAN) technology, based on IEEE 802.16... more

Authorization, authentication, and accounting schemes for WiMAX (Worldwide Interoperability for Microwave Access) are the focus of this paper. WiMAX works as a wireless metropolitan area network (MAN) technology, based on IEEE 802.16 specifications, which was designed to provide high-throughput wireless broadband connections (up to 70 Mbps for fixed scheme and up to 15 Mbps for mobile scheme) over long distances (up to 30 miles) , which is described as a "framework for the evolution of wireless broadband". The main focus of the authentication and authorization is based on the privacy key management $extensible authentication protocol for pairwise key manegement "EAP-PKM" and the accounting issue

The use of digital technologies in providing health care services is collectively known as eHealth. Considerable progress has been made in the development of eHealth services, but concerns over service integration, large scale deployment,... more

The use of digital technologies in providing health care services is collectively known as eHealth. Considerable progress has been made in the development of eHealth services, but concerns over service integration, large scale deployment, and security, integrity and confidentiality of sensitive medical data still need to be addressed. This paper presents a solution proposed by the Data Capture and Auto Identification Reference (DACAR) project to overcoming these challenges. The key contributions of this paper include a Single Point of Contact (SPoC), a novel rule based information sharing policy syntax, and Data Buckets hosted by a scalable and cost-effective Cloud infrastructure. These key components and other system services constitute DACAR's eHealth platform, which allows the secure capture, storage and consumption of sensitive health care data. Currently, a prototype of the DACAR platform has been implemented. To assess the viability and performance of the platform, a demonstration application, namely the Early Warning Score (EWS), has been developed and deployed within a private Cloud infrastructure at Edinburgh Napier University. Simulated experimental results show that the end-to-end communication latency of 97.8% of application messages were below 100ms. Hence, the DACAR platform is efficient enough to support the development and integration of time critical eHealth services. A more comprehensive evaluation of the DACAR platform in a real life clinical environment is under development at Chelsea & Westminster Hospital in London.

Current intrusion detection systems work in isolation front access control for the application the systems aim to protect. The lack of coordination and inter-operation between these components prevents detecting and responding to ongoing... more

Current intrusion detection systems work in isolation front access control for the application the systems aim to protect. The lack of coordination and inter-operation between these components prevents detecting and responding to ongoing attacks in real time, before they cause damage. To address this, we apply dynamic authorization techniques to support fine-grained access control and application level intrusion detection and response capabilities. This paper describes our experience with integration of the Generic Authorization and Access Control API (GAA-API) to provide dynamic intrusion detection and response for the Apache Web Server The GAA-API is a generic interface which may be used to enable such dynamic authorization and intrusion response capabilities for many applications.

In this paper, we present a novel approach for specification of invocable semantic Web resources in a unified manner. Our approach enables specification of Web services, composite Web services, Web pages and Web sites with one single... more

In this paper, we present a novel approach for specification of invocable semantic Web resources in a unified manner. Our approach enables specification of Web services, composite Web services, Web pages and Web sites with one single process description language in a unified manner. The basic idea behind our work is that different types of invocable Web resources differ mainly in the communication protocol and message formats. The language abstracts from various communication protocols and message formats and hence enables modeling of business logic without worrying much about technical details. Our approach in contrast to existing annotation techniques does not enforce the providers to modify their Web resources.

Nowadays, Grid has become a leading technology in distributed computing. Grid poses a seamless sharing of heterogeneous computational resources belonging to different domains and conducts efficient collaborations between Grid users. The... more

Nowadays, Grid has become a leading technology in distributed computing. Grid poses a seamless sharing of heterogeneous computational resources belonging to different domains and conducts efficient collaborations between Grid users. The core Grid functionality defines computational services which allocate computational resources and execute applications submitted by Grid users. The vast models of collaborations and openness of Grid system require a secure, scalable, flexible and expressive authorization model to protect these computational services and Grid resources. Most of the existing authorization models for Grid have granularity to manage access to service invocations while behavioral monitoring of applications executed by these services remains a responsibility of a resource provider. The resource provider executes an application under a local account, and acknowledges all permissions granted to this account to the application. Such approach poses serious security threats to breach system functionality since applications submitted by users could be malicious. We propose a flexible and expressive policy-driven credential-based authorization system to protect Grid computational services against a malicious behavior of applications submitted for the execution. We split an authorization process into two levels: a coarse-grained level that manages access to a computational service; and a fine-grained level that monitors the behavior of applications executed by the computational service. Our framework guarantees that users authorized on a coarse-grained level behave as expected on the fine-grained level. Credentials obtained on the coarse-grained level reflect on fine-grained access decisions. The framework defines trust negotiations on coarse-grained level to overcome scalability problem, and preserves privacy of credentials and security policies of, both, Grid users and providers. Our authorization system was implemented to control access to the Globus Computational GRAM service. A comprehensive performance evaluation shows the practical scope of the proposed system.

The main aim of this paper is to propose a set of action concepts useful for describing organised interaction. These action concepts focus on two distinctions: the distinction between direct and indirect action, and the distinction... more

The main aim of this paper is to propose a set of action concepts useful for describing organised interaction. These action concepts focus on two distinctions: the distinction between direct and indirect action, and the distinction between successful and not necessarily successful action. The formal characterisation of these concepts is given by means of modal logic, following the same tradition in the logical characterisation of act descriptions as employed by Kanger (1972) and Porn (1970). The modal action operators proposed are also combined with a deontic logic and a conditional logic, in order to illustrate their application to the analysis of some simple organisations. The focus of interest is on the notion of transmission of agency, and on the characterisation of the conditions under which an organisation recognises that an agent has fulfilled the responsibilities assigned to him

In this paper, three random access control mechanisms based on the well-known Slotted ALOHA, NP-CSMA, and 1P-CSMA protocols are presented. The basic idea is to limit the number of transmissions and retransmissions at high traffic loads in... more

In this paper, three random access control mechanisms based on the well-known Slotted ALOHA, NP-CSMA, and 1P-CSMA protocols are presented. The basic idea is to limit the number of transmissions and retransmissions at high traffic loads in order to minimize collisions while keeping system stability. A new medium-access control protocol called Adaptive Traffic Load (ATL) is proposed. With ATL, all users are assigned authorization of transmission probabilities that vary according to the prevailing average traffic conditions in the system. ATL ensures that the system throughput is kept constant at its maximum value regardless of the traffic load. A mathematical analysis to calculate the probability density function of the access delay in the ATL protocol under the assumption of infinite user population is also presented. Mean access delay follows increases exponentially with respect to the traffic load when conventional random access protocols are used. However, it follows a linear function with respect to the traffic load when ATL is used. The average traffic load of the system is an input of the ATL protocol in order to assign access authorization probabilities to all users attempting to access the network. A simple algorithm for traffic load estimation based on the probability of finding empty slots in the system within an estimation period is proposed in this paper to asses the average traffic load. In the numerical evaluations of ATL, the Enhanced Data for GSM Evolution (EDGE) system is considered as a case study. For high arrival rates, channel utilization can be low in EDGE even if the system has sufficient capacity to serve incoming data users. A mathematical analysis of ATL-Slotted ALOHA as well as ATL-CSMA is presented. In the case of ATL-CSMA, system throughput varies according to the cell size. Hence, the ATL protocol is evaluated in picocell, microcell and macrocell environments as recommended by ITU-R. Also, the performance of EDGE is evaluated in terms of average data rate and packet delay for both S-ALOHA and ATL S-ALOHA considering long range dependent traffic type.