BOSTON, MA -- Convenience and petroleum retailers are using a simple method to help deter credit card fraud: asking a question.

By asking card-carrying customers for their zip code before making a transaction, retailers are able to cut down on credit fraud by thieves who have no idea what zip code is associated with the card, reports the Boston Globe.

“A thief usually won't know the zip code associated with the card he's using. So requiring the zip code is a simple way to reduce fraudulent purchases,” writes the newspaper, adding that petroleum retailers say they are asking customers for their zip code in areas where credit fraud is significant.

“It is a geographical kind of thing, in a direct response to areas where there has been a high incidence of credit card fraud,” ExxonMobil spokeswoman Betsy Eaton told the newspaper. The company is planning to adopt zip-code authorization at select stations that use its Speedpass contactless payment system.

In 2001, Walgreens began demanding zip codes from customers who pay with American Express cards, which Walgreens spokeswoman Tiffani Bruce says is an American Express-sponsored program “that is essentially fraud protection,” notes the Globe.

Meanwhile, MasterCard prohibits merchants from asking customers for their zip codes, except at “unattended devices” such as fuel dispensers or for purchases made over the phone, by mail or over the Internet.

The newspaper writes that the manager of Roy’s Mobil in Dorchester said his station has been using zip-code authorization for several years. A survey conducted by the Boston Globe found that self-serve dispensers at Mobil stations in Roxbury and Mattapan require customers to key in their zip codes.

One customer said that entering a zip code at the pump is “odd,” while another called the practice “stupid.”

Meanwhile, companies such as Dresser Inc. in Dallas, Texas, are hoping to solve fraud issues by developing biometric payment systems, which identify the customer by reading their fingerprint. When a customer steps up to the pump, he or she would touch a fingerprint scanner mounted on the dispenser, which would then associate the print with the customer’s credit card.

“'I think biometrics is going to be the next up-and-coming payment technology, if the public will accept it,” Dresser spokesman Mike Hardin told the newspaper, adding that the widespread growth of biometric systems at the pump is “just a matter of time.”

“I think credit cards as we know them now will eventually disappear and go away,” Hardin said.