Safavi-Naini, Reyhaneh AlsadatBarker, Kenneth EdwinJafari, Mohammad2013-09-062013-11-122013-09-062013Jafari, M. (2013). Modelling and Enforcing Purpose in Privacy Policies (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/26953http://hdl.handle.net/11023/924Privacy concerns are among the most significant side effects of advances in computer and networking technologies. Expressing and enforcing privacy policies is necessary to ensure that processing of personal information in these systems does not violate privacy of individuals. Privacy laws and regulations, as well as various privacy policy languages and privacy-preserving systems show no disagreement in that purpose of use has a key role in privacy policies and is an important factor in controlling access to personal data. In the current literature on privacy, purposes have been treated mostly as opaque labels with little or no semantics. The resulting ambiguities have made purposes susceptible to malicious or inadvertent misinterpretations. Consequently, enforcing purpose-based policies has also remained a challenge. In this research, we address these problems. We develop a framework that defines purposes formally and provides a formal language for expressing purpose constraints, as well as the corresponding method for evaluating them in the context of a workflow. The semantics of this language are defined over an abstract model of business workflows. We show how purpose constraints can be linked to access control rules to form purpose-based policies and develop an enforcement mechanism in the form of a workflow reference monitor to ensure compliance to such policies. We also show how a simple form of such a reference monitor can be implemented using XACML, a common open standard access control system in the industry.engUniversity 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.Computer SciencePurposePrivacyWorkflowdoctoral thesis10.11575/PRISM/26953