Abstract: System and methodology providing automated or “proactive” network security (“active” firewall) are described. The system implements methodology for verifying or authenticating communications, especially between network security components thereby allowing those components to share information. In one embodiment, a system implementing an active firewall is provided which includes methodology for verifying or authenticating communications between network components (e.g., sensor(s), arbiter, and actor(s)), using cryptographic keys or digital certificates. Certificates may be used to digitally sign a message or file and, in a complementary manner, to verify a digital signature. At the outset, particular software components that may participate in authenticated communication are specified, including creating a digital certificate for each such software component.