29 research outputs found
Towards a Formal Model of Privacy-Sensitive Dynamic Coalitions
The concept of dynamic coalitions (also virtual organizations) describes the
temporary interconnection of autonomous agents, who share information or
resources in order to achieve a common goal. Through modern technologies these
coalitions may form across company, organization and system borders. Therefor
questions of access control and security are of vital significance for the
architectures supporting these coalitions.
In this paper, we present our first steps to reach a formal framework for
modeling and verifying the design of privacy-sensitive dynamic coalition
infrastructures and their processes. In order to do so we extend existing
dynamic coalition modeling approaches with an access-control-concept, which
manages access to information through policies. Furthermore we regard the
processes underlying these coalitions and present first works in formalizing
these processes. As a result of the present paper we illustrate the usefulness
of the Abstract State Machine (ASM) method for this task. We demonstrate a
formal treatment of privacy-sensitive dynamic coalitions by two example ASMs
which model certain access control situations. A logical consideration of these
ASMs can lead to a better understanding and a verification of the ASMs
according to the aspired specification.Comment: In Proceedings FAVO 2011, arXiv:1204.579
Formalisation and Implementation of the XACML Access Control Mechanism
We propose a formal account of XACML, an OASIS standard adhering to the Policy Based Access Control model for the specifica- tion and enforcement of access control policies. To clarify all ambiguous and intricate aspects of XACML, we provide it with a more manageable alternative syntax and with a solid semantic ground. This lays the basis
for developing tools and methodologies which allow software engineers to easily and precisely regulate access to resources using policies. To demonstrate feasibility and effectiveness of our approach, we provide a software tool, supporting the specification and evaluation of policies and access requests, whose implementation fully relies on our formal development
Towards Model-Driven Development of Access Control Policies for Web Applications
We introduce a UML-based notation for graphically modeling
systemsā security aspects in a simple and intuitive
way and a model-driven process that transforms graphical
specifications of access control policies in XACML. These
XACML policies are then translated in FACPL, a policy
language with a formal semantics, and the resulting policies
are evaluated by means of a Java-based software tool
Formalisation and Implementation of the XACML Access Control Mechanism
Abstract. We propose a formal account of XACML, an OASIS standard adhering to the Policy Based Access Control model for the specification and enforcement of access control policies. To clarify all ambiguous and intricate aspects of XACML, we provide it with a more manageable alternative syntax and with a solid semantic ground. This lays the basis for developing tools and methodologies which allow software engineers to easily and precisely regulate access to resources using policies. To demonstrate feasibility and effectiveness of our approach, we provide a software tool, supporting the specification and evaluation of policies and access requests, whose implementation fully relies on our formal development
A Formal Approach to Specification, Analysis and Implementation of Policy-Based Systems
The design of modern computing systems largely exploits structured sets of declarative rules called policies. Their principled use permits controlling a wide variety of system aspects and achieving separation of concerns between the managing and functional parts of systems.
These so-called policy-based systems are utilised within different application domains, from network management and autonomic computing to access control and emergency handling. The various policy-based proposals from the literature lack however a comprehensive methodology supporting the whole life-cycle of system development: specification, analysis and implementation. In this thesis we propose formally-defined tool-assisted methodologies for supporting the development of policy-based access control and autonomic computing systems.
We first present FACPL, a formal language that defines a core, yet expressive syntax for the specification of attribute-based access control policies. On the base of its denotational semantics, we devise a constraint-based analysis approach that enables the automatic verification of different properties of interest on policies.
We then present PSCEL, a FACPL-based formal language for the specification of autonomic computing systems. FACPL policies are employed to enforce authorisation controls and context-dependent adaptation strategies. To statically point out the effects of policies on system behaviours, we rely again on a constraint-based analysis approach and reason on progress properties of PSCEL systems.
The implementation of the languages and their analyses provides us some practical software tools. The effectiveness of the proposed solutions is illustrated through real-world case studies from the e-Health and autonomic computing domains
VĆ©rification et validation de politiques de contrĆ“le d'accĆØs dans le domaine mĆ©dical
Dans le domaine meĢdical, la numeĢrisation des documents et lāutilisation des dossiers patient eĢlectroniques (DPE, ou en anglais EHR pour Electronic Health Record) offrent de nombreux avantages, tels que la faciliteĢ de recherche et de transmission de ces donneĢes. Les systeĢmes informatiques doivent reprendre ainsi progressivement le roĢle traditionnellement tenu par les archivistes, roĢle qui comprenait notamment la gestion des acceĢs aĢ ces donneĢes sensibles. Ces derniers doivent en effet eĢtre rigoureusement controĢleĢs pour tenir compte des souhaits de confidentialiteĢ des patients, des reĢgles des eĢtablissements et de la leĢgislation en vigueur. SGAC, ou Solution de Gestion AutomatiseĢe du Consentement, a pour but de fournir une solution dans laquelle lāacceĢs aux donneĢes du patient serait non seulement baseĢe sur les reĢgles mises en place par le patient lui-meĢme mais aussi sur le reĢglement de lāeĢtablissement et sur la leĢgislation. Cependant, cette liberteĢ octroyeĢe au patient est source de divers probleĢmes : conflits, masquage des donneĢes neĢcessaires aux soins ou encore tout simplement erreurs de saisie. Pour effectuer ces veĢrifications, les meĢthodes formelles fournissent des moyens fiables de veĢrification de proprieĢteĢs tels que les preuves ou la veĢrification de modeĢles. Cette theĢse propose des meĢthodes de veĢrification adapteĢes aĢ SGAC pour le patient : elle introduit le modeĢle formel de SGAC, des meĢthodes de veĢrifications de proprieĢteĢs. Afin de mener ces veĢrifications de manieĢre automatiseĢe, SGAC est modeĢliseĢ en B et Alloy ; ces diffeĢrentes modeĢlisations donnent acceĢs aux outils Alloy et ProB, et ainsi aĢ la veĢrification automatiseĢe de proprieĢteĢs via la veĢrification de modeĢles ou model checking.Abstract : In healthcare, data digitization and the use of the Electronic Health Records (EHR) offer several benefits, such as the reduction of the space occupied by data, or the ease of data search or data exchanges. IT systems must gradually take up the archivistās role by managing the accesses over sensitive data, which have to be compliant with patient wishes, hospital rules, as well as laws and regulations. SGAC, or Solution de Gestion AutomatiseĢe du Consentement (Automated Consent Management Solution), aims to provide a solution in which access to patient data would be based on patient rules, hospital rules and laws. However, the freedom granted to the patient can cause several problems : conflicts, concealment of crucial data needed to treat the patient adequately, and data-capture errors. Therefore, verification and validation of policies are essential : formal methods provide reliable ways, such as proofs or model checking, to conduct verifications of properties. This thesis provides verification methods applied on SGAC for the patient : it introduces the formal model of SGAC, methods to verify properties such as data access resolution, hidden data detection or redundant rule identification. Modeling of SGAC in B and Alloy provides access to the tools Alloy and ProB, and thus, automated property verification through model checking
On Usage Control for Data Grids: Models, Architectures, and Specifications
This thesis reasons on usage control in Data Grids, by presenting
models, architectures and specifications. This work is a step
toward a continuous monitoring and control of the data access and
usage in a Data Grid. First, the thesis presents a background on
Grids, security, and security for Grids, by making an abstraction
to the current Grid implementations. We argue that usage control
in Data Grids should be considered as a process composed
by two black boxes. We analysed the requirements for Grid security,
and propose a distributed usage control model suitable for
Grids and distributed systems alike. Then, we apply such model
to a Data Grid abstraction, and present a usage control architecture
for Data Grids that uses the functional components of the
currents Grids. We also present an abstract specification for an
enforcing mechanism for usage control policies. To do so, we use
a formal requirement engineering methodology with a bottom-up
approach, that proves that the specification is sound and complete.
With the methodology, we show formally that such abstract specification
can enforce all the different typologies of usage control
policies. Finally, we consider how existing prototypes can fit in
the proposed architecture, and the advantages derived from using
Semantic Grid techologies for the specification of policies subjects
and objects