  Firewalls have long been in use to protect local networks from threats of the
larger Internet. Although firewalls are effective in preventing attacks
initiated from outside, they are vulnerable to insider threats, e.g., malicious
insiders may access and alter firewall configurations, and disable firewall
services. In this paper, we develop an innovative distributed architecture to
obliviously manage and evaluate firewalls to prevent both insider and external
attacks oriented to the firewalls. Our proposed structure alleviates these
issues by obfuscating the firewall rules or policies themselves, then
distributing the function of evaluating these rules across multiple servers.
Thus, both accessing and altering the rules are considerably more difficult
thereby providing better protection to the local network as well as greater
security for the firewall itself. We achieve this by integrating multiple areas
of research such as secret sharing schemes and multi-party computation, as well
as Bloom filters and Byzantine agreement protocols. Our resulting solution is
an efficient and secure means by which a firewall may be distributed, and
obfuscated while maintaining the ability for multiple servers to obliviously
evaluate its functionality.
