Preventing credit card forgery.

• Position: Use of electronic fingerprints

Researchers at Washington University have invented a technique that could eliminate the majority of the $1,000,000,000 lost to credit card fraud each year in the U.S. It also could change the way people and industries safeguard and authenticate information.

The technique identifies "electronic fingerprints" of objects that carry magnetically recorded data. It can provide positive identification of any object or document that carries such magnetic information--from credit cards, cardkeys, and security cards to music and data tapes and other computer software. The technique reads a unique magnetic signature that is virtually impossible for a forger to duplicate and can protect the recorded information against tampering.

Ronald S. Indeck, associate professor of electrical engineering, and Marcel W. Muller, professor of electrical engineering, discovered that all magnetic media are marked with a unique, permanent magnetic signature that can be identified electronically. Scientists had thought that the random arrangements of millions of magnetic microparticles that comprise magnetic information devices were only a nuisance that corrupted the desired information. Each microparticle grain is one-500th the thickness of a strand of human hair. Instead, Indeck and Muller have proven that the effects of this very randomness are permanently, electronically identifiable for each small region of a magnetic device.

Credit cards, for instance, have a magnetic stripe above the owner's signature, with three parallel lines that look like railroad tracks and cross ties that contain the digital "ones and zeros" of the credit card information. The magnetism is carried by iron oxide particles--literally rust dust--encased in a plastic binder. Each of the millions of tiny grains, scattered about like spattered paint, is magnetic.

Information is imprinted on the particles by magnetizing them with a strong magnetic field. (That is why the information can be lost if the card accidentally is exposed to another magnetic field.) The information is recognized and turned into an electrical signal by a recording read head in the card reader. When a sales clerk runs a credit card through a magnetic card reader, the result is a digital confirmation of the...