Contexts and Context-based Access Control Model

1
Contexts and Context-based Access Control Model

• PhD Dissertation Progress Report
• Candidate Alvaro E. Escobar
• Advisors
• Dr. Maria Petrie
• Dr. Eduardo Fernandez

Department of Computer Science and
Engineering Florida Atlantic University, Boca
Raton FL. 12/15/2005
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Agenda

• What is Context?
• Context Models
• What is Profile
• Profile Models
• Policy and Access Control
• Access Control Models
• Conclusions
• Future Work

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What is Context?

• The set of facts and/or circumstances that
  surround a situation or event. Google.
• The location and identities of nearby people and
  objects and changes to those objects. Sch95
• The logical set of resources accessible to a
  client during a service session depending on
  several factors, such as client location, access
  device capabilities, management policies of the
  access locality, subscribed services, user
  preferences, and level of trust. Bel03 Cor04
• The composition of context elements which belong
  to either physical or organizational contexts.
  The physical context identifies spaces, locations
  and devices. The organizational context includes
  roles, groups, calendars, activities, processes
  and applications. Kir05
• Is a process of interacting with an ever-changing
  environment composed of reconfigurable, mobile
  and distributed resources. Cou05.
• Is a distinction between the notion of an instant
  snapshot of observable variables (a situation)
  and the composition of those observable variables
  over time (a context) Cou02.

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Context Models
Corradis Context and Access Control Model
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Context Models
Kirsch-Pinheiros Class model for Context Part
1 (Taken from Kir05)
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Context Models
Kirsch-Pinheiros Class model for Context Part
2 (Taken from Kir05)
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Context Models
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What is Context made of?

• Critical sub-processes of a context are
• Collect the set of locally available resources.
  (resources potentially visible in the users
  physical location)
• Filter the visible resources through access
  control policies. (refined potentially visible
  resources)
• Map them onto the users goals, preferences and
  activities described by profiles. (refine
  resources even more)
• Resources vs Observables. (What about time?)

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What is a Profile?

• Profiles represent characteristics, capabilities,
  and requirements of users, devices, and service
  components. Bel03.
• User profiles personal preferences, interests,
  privacy requirements, and subscribed services.
• Device profiles hardware/software
  characteristics of devices.
• Service component profiles service interface,
  properties for binding management decisions.
• Site profiles All resources available at one
  location.

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What is a Profile?

• Descriptions of users potential contexts and
  filtering rules that describe the users
  preferences, given a context Kir05
• Comprehensive Structured Context Profiles (CSCP)
  based on the Resource Description Framework (RDF)
  Buc04,Bra01

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Profile Models
Corradis Profile Model
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Profile Models
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Policy and Access Control

• Policies express the choices of a ruling system
  behavior, in terms of the actions subjects
  can/must operate upon resources.Bel03
• Access control policies specify the actions
  subjects are allowed to perform on resources
  depending on various types of conditions, e.g.,
  subject identity and resource state
• Obligation policies define the actions subjects
  must perform on resources when specified
  conditions occur.
• The automatic qualification of accessible
  resources depends on the client context, the
  current enforced management policies and the
  users personal preferences (profiles). Cor04

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Access Control Model
Corradis Access Control Model
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Context and CBAC Model
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Conclusions

• Context is a fundamental concept in mobile
  systems.
• Different researchers use different variations of
  context.
• We have tried here to unify and clarify this
  concept from three definitions of context.
• We produced a model that summarizes their most
  relevant aspects.
• This unified model can be expressed as a pattern
  and can be used as a guideline for the design of
  mobile systems.

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Future Work

• Work on the pattern model and characteristics.
• Paper submission for International Workshop on
  Research Challenges in Security and Privacy for
  Mobile and Wireless Networks (WSPWN06) - March
  15-16, 2006, Miami FL.
• Context-Aware Web Services Distributed and
  Parallel Databases Journal - Submission deadline
  March 15, 2006.
• AMCIS Minitrack on Mobile Services - Submission
  deadline March 1, 2006.
• Dissertation document completed by end of Summer
  06.

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Contexts and Context-based Access Control Model

• References
• Bel03 P. Bellavista, A. Corradi, R. Montanari,
  C. Stefanelli, Context-Aware Middleware for
  Resource Management in the Wireless Internet,
  IEEE Transactions on Software Engineering. Vol.
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• Cor04 A. Corradi, R. Montanari, D. Tibaldi,
  Context-Based Access Control Management in
  Ubiquitous Environments, Network Computing and
  Applications, Proceeding of the Third IEEE
  International Symposium on (NCA'04), August 30 -
  September 01, 2004, Boston, MA.
• Cou05 J. Coutaz, J. L. Crowley, S. Dobson D.
  Garlan. Context is key. Communications of the
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• Cou02 J. Coutaz and G. Rey. Foundations for a
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  Atlantic University.
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  for Collaborative Web Systems Adapting the
  Awareness Information to the Users Context 2005
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  13-17, 2005, Santa Fe, New Mexico, USA.
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• Sch95 W. N. Schilit. A System Architecture for
  Context-Aware Mobile Computing. PhD thesis
  dissertation. Columbia University, 1995.