Authorized workflow schemas: deciding realizability through \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathsf{LT

Many business processes are modeled as workflows, which often need to comply with business rules, legal requirements, and authorization policies. Workflow satisfiability is the problem of determining whether there exists a workflow instance that realizes the workflow specification while simultaneously complying with such constraints. This problem has already been studied by the computer security community, with the development of algorithms and the study of their worst-case complexity. These solutions are often tailored to a particular workflow model and are, therefore, of little or no use in analyzing different models; their worst-case complexities are likely to be an unreliable judge of their feasibility; and they lack support for other forms of analysis such as the determination of the smallest number of users required to satisfy a workflow specification. We propose model checking of an NP-complete fragment $$\mathsf{LTL }(\mathsf{F })$$ of propositional linear-time temporal logic as an alternative solution. We report encodings in LTL(F) that can compute a set of solutions (thus deciding satisfiability), compute minimal user bases and a safe bound on the resiliency of satisfiability under the removal of users. These theoretical contributions are validated through detailed experiments whose results attest to the viability of our proposed approach.

[1]  Andreas Podelski,et al.  Boolean and Cartesian abstraction for model checking C programs , 2001, International Journal on Software Tools for Technology Transfer.

[2]  Jason Crampton A reference monitor for workflow systems with constrained task execution , 2005, SACMAT '05.

[3]  Vijayalakshmi Atluri,et al.  Inter-instance authorization constraints for secure workflow management , 2006, SACMAT '06.

[4]  Marco Pistore,et al.  NuSMV 2: An OpenSource Tool for Symbolic Model Checking , 2002, CAV.

[5]  Michael Westergaard,et al.  Better Algorithms for Analyzing and Enacting Declarative Workflow Languages Using LTL , 2011, BPM.

[6]  Jason Crampton,et al.  Delegation and satisfiability in workflow systems , 2008, SACMAT '08.

[7]  Michael Huth,et al.  Synthesizing and Verifying Plans for Constrained Workflows : Transferring Tools from Formal Methods , 2011 .

[8]  Moshe Y. Vardi,et al.  LTL Satisfiability Checking , 2007, SPIN.

[9]  Raghava Rao Mukkamala,et al.  Declarative Event-Based Workflow as Distributed Dynamic Condition Response Graphs , 2011, PLACES.

[10]  Nick Russell,et al.  Foundations of Process-Aware Information Systems , 2007 .

[11]  Michael Huth,et al.  On the Modeling and Verification of Security-Aware and Process-Aware Information Systems , 2011, Business Process Management Workshops.

[12]  Ninghui Li,et al.  Satisfiability and Resiliency in Workflow Systems , 2007, ESORICS.

[13]  Holger Hermanns,et al.  Proceedings of the 19th international conference on Computer aided verification , 2007 .

[14]  Wil M. P. van der Aalst,et al.  Declarative workflows: Balancing between flexibility and support , 2009, Computer Science - Research and Development.

[15]  Moshe Y. Vardi,et al.  A Multi-encoding Approach for LTL Symbolic Satisfiability Checking , 2011, FM.

[16]  Elisa Bertino,et al.  The specification and enforcement of authorization constraints in workflow management systems , 1999, TSEC.

[17]  Wil M. P. van der Aalst,et al.  Workflow Patterns , 2004, Distributed and Parallel Databases.

[18]  Pierre Wolper,et al.  Reasoning About Infinite Computations , 1994, Inf. Comput..

[19]  Glynn Winskel,et al.  Event Structures , 1986, Advances in Petri Nets.

[20]  A. Prasad Sistla,et al.  The complexity of propositional linear temporal logics , 1982, STOC '82.

[21]  David A. Schmidt,et al.  Program Analysis as Model Checking of Abstract Interpretations , 1998, SAS.

[22]  Thomas W. Reps,et al.  Revamping TVLA: Making Parametric Shape Analysis Competitive , 2007, CAV.

[23]  Jason Crampton,et al.  The consistency of task-based authorization constraints in workflow , 2004, Proceedings. 17th IEEE Computer Security Foundations Workshop, 2004..

[24]  Ravi S. Sandhu,et al.  Role-Based Access Control Models , 1996, Computer.