One reason for the threat of a cyber attack is the open architecture of the digital revolution. The highly networked environment has been built on an intentionally insecure foundation: ARPANET, the Internet predecessor, which devised packet switching as a means of communication, was not meant to be secure. As a result, the interconnected vital national functions, from credit card transactions to emergency services, present a target rich environment for cyberterrorists. With the United States as the dominant military force in the world, cyberwar has become the preferred option of smaller players. The way to prepare for a cyberdefense in the digital age is problematic. One of the first problems is determining who the enemy is. Distinguishing a terrorist from a hacker, or a foreign intelligence agent from a competitor stealing secrets is not easy. Today, the culprit has to be apprehended before it is determined who has jurisdiction to investigate. There is also a need to redefine who the defender will be. Many of the future defenders will be young computer wizards. The sandal culture is challenging the wingtips and the combat boots. A key to the success of cyberdefense is realizing that it is no longer armed troops that stand between the United States and its enemies, but it is the entire cyberworld. Private industry has its own large stake in security. While governmental actions are essential, the business community must assume much more responsibility for protecting itself. Business should also share information among themselves. In addition, the Federal Government should provide more support for research on the threats from cyberspace. Finally, the United States should train for a cyberattack just as it does for conventional or nuclear warfare.