In typical military operations, the advantage goes to the offense because the initiator controls the timing and is able to concentrate forces. A good defense is designed to undermine the advantage of the offense. Proactive defense approaches include: masking (obfuscation), maneuvering, and hardening of critical capabilities. The other alternative, which is often characterized as resiliency or mission assurance, is to employ methods which deny the objectives of the offense. The expertise resident in the hacker community can improve both proactive defense and mission assurance.