A billion dollars' worth of fraudulent checks were cashed last year, many of them via simple electronic alteration of office-printed documents. That's the estimate of Washington, D.C., consultant Frank Abagnale, and he ought to know, having personally forged $2.5 million worth before the feds put a stop to a brilliant career. Indeed, rues Abagnale, "color copiers and scanners have made it 10 times easier today."

Now on the right side of the law, Abagnale advises corporate America on how to protect against felonious schemers like his old self. One result: business-forms manufacturer Standard Register has added safeguards. Among them:

* Paper embedded with artificial watermarks so faint they cannot be copied.

* Numerical fonts with distinct shapes said to be impossible to modify.

* A colored background that disappears -- replaced by the letters V-O-I-D -- when the check is tampered with.

* Chemically treated toner that inseparably bonds laser-printer ink to paper.

For more information on fraud-prevention products, ask for the specialty-products department at Standard Register, at 513-443-1000. -- Robert A. Mamis