Our work so far has resulted in the development of an appropriate syntax, a definition of the semantics, and an initial evaluator of composite trust for a system of incorporating stochastic attributes of their reliability. Additional details can be found in a recent technical report.
Our current work is focusing on the development of a centralized evaluator for partial trust delegations that will (1) construct authorization networks from a library of QTM delegation credentials and (2) compute the expected reliability of an authorization network in the context of a stochastic attribute.
We further intend to explore the encoding of multiple independent or related reliability attributes into delegations and their evaluation. In particular, we are investigating the incorporation of an additional "availability" metric that could be potentially used to develop a framework for determining "weak links" in an authorization schema or administrative policy.