Keeping The Hackers At Bay

When it comes to cyberwarfare, America has a secret weapon: Georgetown University professor Dorothy Denning. Battles in cyberspace are high-tech brain races: you win by being the first to recognize the weaknesses of a new technology--often hacking it yourself--and then figuring out how to protect it.

This is what Denning has been doing for nearly three decades. In the 1970s, when most people thought information security meant locking your file cabinets, Denning devised a way for federal agencies such as the IRS to release vital information while keeping its most sensitive data secure. As computer systems became more complex, she discovered a system now widely used for detecting intruders in real time, rather than combing through log-in records after the fact.

And now she's pioneering a new field she calls geo-encryption. Working with industry, Denning has developed a way to keep information undecipherable until it reaches its location, as determined by GPS satellites. Movie studios, for example, have been afraid to release films digitally for the same reasons record companies hate Napster: once loose on the Internet, there's little to stop someone from posting the latest blockbuster DVD on the Web for all to see and download. With Denning's system, however, only subscribers in specified locations--such as movie theaters--would be able to unscramble the data. The technology works as well for national security as it does for Harry Potter. Coded messages that the State Department sends its embassies, for example, could only be deciphered in the embassy buildings themselves, greatly reducing the risk of interception.

For now, Denning says, terrorists "may want to bring down the power grid or the finance system, but it's still easier to blow up a building." If she's right, it's due in large part to her.