Quality-of-Protection (QoP): A Quantitative Methodology to Grade Security Services

A tree based quality of protection (QoP) evaluation method for cyber system is presented. The elements of a security system structure are represented as normalized weighted tree. We show that our weighted tree representation of security system structure is informative and useful. Based on this unique representation QoP evaluation methodology is introduced and the foundations of QoP modeling and evaluation are established. The important steps in the evaluation process are the introduction of normalized weighted tree which establishes the hierarchy of the requirements of a secure system and the formulation of the normalized weighted tree. This is used to compute the QoP in a quantitative manner. We demonstrate through several examples, how the proposed methodology can assess QoP from a holistic view.