Fong, Philip W. L.Khan, Arif Akram2016-11-292016-11-292012-09http://hdl.handle.net/1880/51754Bibliography: p. 72-76A workflow authorization model is defined in the framework of Relationship-Based Access Control (ReBAC), in which the protection state is a social network. Armed with this model, a new decision problem called workflow feasibility is studied. The goal is to ensure that the space of protection states contains at least one member in which the workflow specification can be executed to completion. A sufficient condition is identified under which feasibil­ity can be decided by a refutation procedure that is both sound and complete. A formal specification language, based on a monotonic fragment of the Propositional Dynamic Logic (PDL), is proposed for specifying protection state spaces. The adoption of this language renders workflow feasibility NP-complete in the general case but polynomial-time decidable for an important family of workflows. A model checker for this POL-based language is im­plemented. Hybridization of this PDL-fragment is examined. Satisfiability and feasibility of workflows with XOR-patterns are analyzed as well.vi, 76 leaves : ill. ; 30 cm.engAttribution Non-Commercial 4.0 InternationalUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.http://creativecommons.org/licenses/by-nc/4.0/master thesis10.11575/PRISM/32801