In the military, most new weapons systems go through an evaluation, or proof-of-concept, phase. These are not full-power tests, but baby steps to show that key technology should work as advertised.

This sort of testing takes place not only with missiles and bombs but also with the cybernetic implements of information warfare. Indeed, any group that is developing tools to disrupt an adversary's information systems would be downright irresponsible if it did not conduct proof-of-concept demonstrations as part of its R&D process. These tests would not cause great harm: instead, they would be designed to whet the appetite of officials higher up the command chain.

And what would a proof-of-concept demonstration for an information warfare weapon look like? Possibly a lot like the computer virus attacks the Internet has experienced in recent years. I suspect that some of these electronic attacks were actually the results of deliberate tests for a future attack that could have truly dire consequences.

To understand my alarm, you need to understand the anatomy of computer viruses and their cousins, worms. Most of these hostile programs have three parts. The first, the "exploit," is the technique the virus or worm uses to break into systems. Most exploits take advantage of a known security flaw-for example, the classic "buffer overflow," in which an excess of incoming data corrupts the information already stored in memory. The second part, the "propagation engine," is the code that targets computers for attack. And the third, the "payload," does the actual damage.