timeTree: How to Represent Time Sequence in a Threat Tree.

Threat tree can be used as a tool to represent the threat conditions for certain risks. The conditions are represented as children, and the resulting risk is represented as a father. The relations among conditions could be “and” or “or”, and the resulting risk could be further as a condition for another risk that is the father of the immediate upper layer. Those iteratively representations can finally form a threat tree to tackle all possible risks. However, current threat tree can only describe static risks, and cannot show the dynamics for a threat route, which is a serial of conditions with time sequence for a risk. Thus, in this paper, we propose a tree model with time sequence semantics to extend the representation capabilities of a threat tree. Our model is incrementally enhancement of original threat tree, so that legacy threat tree can remain unamended compatibly. The data structure and algorithms are also proposed to show the usability of the proposed model.