The US Army is reportedly beginning to take an interest in computer viruses – purely for defensive reasons, you understand, but you know how defence has a way of turning into offence. The Army is worried that an enemy might try to infiltrate its battlefield communications systems with viruses, and wants some good ones so that it can study how to defend against them – particularly the control systems in the kinds of smart weapons that looked so effective in the very selective film footage from the Gulf War. But already the military mind is turning its attention on how to infiltrate the other guy’s smart weaponry.