Towards a Notion of Quantitative Security Analysis

The traditional Dolev-Yao model of security limits attacks to “computationally feasible” operations. We depart from this model by assigning a cost to protocol actions, both of the Dolev-Yao kind as well as non traditional forms such as computationally-hard operations, guessing, principal subversion, and failure. This quantitative approach enables evaluating protocol resilience to various forms of denial of service, guessing attacks, and resource limitation. While the methodology is general, we demonstrate it through a low-level variant of the MSR specification language.