Abstract
Previous work at NRL demonstrated the benefits of a security modeling approach for building high assurance systems for particular application domains. This paper introduces an application domain called selective bypass that is prominent in certain network security solutions. We present a parameterized modeling framework for the domain and then instantiate a confidentiality model for a particular application, called the External COMSEC Adaptor (ECA), within the framework. We conclude with lessons we learned from modeling, implementing and verifying the ECA. Our experience supports the use of the application-based security modeling approach for high assurance systems.