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.

Abstract: A cryptographic-enabled messaging system providing a “Policy Management Agent” is described. The Policy Management Agent works in conjunction with a standard mail server, such as an SMTP (Simple Mail Transport Protocol) mail server, to ensure that incoming and outgoing e-mail adheres to the policies that are specified for a given site. Specifically, the Agent intercepts e-mail normally bound for the mail server and checks to make sure that it conforms with policies configured for one's site (e.g., corporate site). If the e-mail adheres to the policies for the site, it is forwarded to the mail server where it is routed to the intended recipient. If the e-mail does not adhere to the policies specified for the site, a message of one's choosing is sent to the client indicating that the e-mail was rejected. In an exemplary embodiment (e.g.

Abstract: A cryptosystem having a Certificate (Key) Server for storing and maintaining certificate or key information in a certificate database is described. The Certificate Server allows clients to submit and retrieve keys from a database based on a set of policy constraints which are set for one's particular site (e.g., company). Access to the Certificate Server is maintained by a Certificate Policy Agent, which makes sure that the policy is enforced for a given site based on the information supplied during the configuration. During operation, the Certificate Server responds to client requests to add, search for, and retrieve certificates. The server accepts or rejects certificates based on configurable parameters enforced by a Certificate Policy Agent. When a certificate is submitted to the server, the Certificate Policy Agent checks to see if it meets the criteria for a given site based on the settings specified during the configuration.