Code, papers and conference slides releated to the Hierarchical Group and Attribute-Based Access Control (HGABAC) project[1,2].
More details on the porject can be found at http://cs1.ca/phd
Code and tests for somne of the Hierarchical Group Attribute Architecture (HGAA) services and an implmentation of the new attribute certificate format from .
Code and tests for a parser for the Hierarchical Group Policy Language version 2 (HGPLv2) from 
 Servos, Daniel, and Sylvia L. Osborn. "HGABAC: Towards a formal model of hierarchical attribute-based access control." International Symposium on Foundations and Practice of Security. 2014.
 Servos, Daniel, and Sylvia L. Osborn. "HGAA: An architecture to support hierarchical group and attribute-based access control." Proceedings of the Third ACM Workshop on Attribute-Based Access Control. 2018.