Doug Johnson, vice president for risk management policy at the American Bankers Association, said that American banks were concerned about security but that there were no plans to move to chip-and-PIN cards. “There are a lot of hurdles,” he said, “both from a cost standpoint as well as a network standpoint, we need to broach.”

It should be noted that chip-and-PIN cards are different from the radio frequency chip that some American credit cards now have, which allows customers to wave their card at a check-out scanner, instead of physically swiping it. Visa’s payWave cards and Expresspay cards from American Express are two examples.

But regardless of the technology used, merchants have a certain amount of control over what kinds of cards they accept. Vélib’, for example, accepts American Express cards whether they have chip-and-PIN technology or not. But it doesn’t accept Visa or MasterCards unless they have the chip-and-PIN technology.

CREDIT card issuers acknowledge the problems but offer few solutions at the moment. Randa N. Ghnaim, a spokeswoman for Visa, said the company was working with banks and merchants across Europe to ensure that they accept magnetic stripe cards in addition to chip-and-PINs.

“We have heard of limited instances where merchants have refused to accept Visa magnetic stripe cards, but by and large, the majority of Visa cards are seamlessly accepted internationally,” she said. “It’s usually a lack of understanding that could lead to any issues rather than any issue related to the type of card a consumer may carry.”

And at least one company, Travelex, the global payment services company, says it is working on a chip-and-PIN card for Americans that could be loaded with up to 6,000 euros or £4,500  about $9,000 or $7,400 at recent exchange rates. But that solution is still at least a year away.

“It’s definitely something we’ve been hearing more and more of,” said Tracy Hammock, a senior vice president at Travelex.