What makes S. Korea cyberattacks so hard to trace?

NEW YORK (AP) - The attacks that knocked South Korean banks and media outlets offline this week appear to be the latest examples of international "cyberwar."

But among the many ways that digital warfare differs from conventional combat: There's often no good way of knowing who's behind an attack.

South Korean authorities said on Thursday that the attack, which shut down scores of cash machines and hampered business, had been traced to an "Internet Protocol" address in China. But that doesn't mean the attack was launched from there. The general assumption in South Korea is that the attack originated in North Korea.

"IP" addresses are, roughly speaking, the phone numbers of the Internet. Each connected computer has a number that identifies it uniquely on the network and so the Chinese IP address implies that a computer in China was involved in the attack.