Dorothy Denning, who for nearly 30 years has been inventing new ways to keep hackers from hacking into computer systems, is a Georgetown professor who invented the idea. In the 1970's, she was head of a project to safeguard data shared by federal agencies, such as the CIA & FBI. In the 1980's, she invented a system to detect hackers as soon as they crack into a system.

Denning's new idea is called "geo-encryption." It is a form of copyright protection that relies on GPS satellites. The information is encrypted until it reaches a precise location as determined by GPS. The system is a big hit with Hollywood movie executives who wish to keep copyrighted material from being shared via the internet, such as in the recent Napster case. Only people in specified locations would be able to unscramble the encrypted data, keeping the information secure from those not authorized to receive it.

The encryption scheme may work well for Hollywood, but it has gotten the interest of the Pentagon. Such a secure transmission scheme would be invaluable to the military for sending information worldwide and especially to commanders in the field. The recipient could only decode the information in one specified location, such as a forward command post.

Geo-encryption could also be a boon to business communications. A private business meeting among corporate heads could be kept safe from industrial espionage. The information, such as a video conference link, would only allow those in two different conference rooms in two different office buildings in two different cities, for example, to be able to access the link. The medical field would benefit by keeping medical records private and viewed only by the doctors who would need to see the information. There wouldn't be any worry about privacy leaks.

The encryption scheme isn't foolproof, however. The main consideration would be to make the encryption device & GPS receiver tamperproof. Even this would not be enough if someone knew how to reproduce GPS signals and spoof the receiver into thinking it's at the correct location for decryption. This may not be easy to do, but it definitely could be done if one knew the GPS algorithm. On the other hand, geo-encryption will go far in protecting systems from hackers.

If you're interested in reading past columns of "Covert Comms," you're in luck. I'm in the process of archiving all my past columns on the internet. This is still a work in progress, but I hope to have them all up soon. They can be found at http://www.geocities.com/n2uhc/covertcomms.html.