More and more credit cards are coming not just with a magnetic strip, but also an ID chip that can be read without being swiped.
It's called radio frequency identification technology, or RFID, and this new technology raises the question: Could those ID numbers and accounts be picked out of your pocket?
In the past, if the wrong person was able to get a hold of your credit card, they could use a device called a skimmer to steal your account information.
Local news from across Southern California
But that's yesterday's technology.
Now a growing number of cards also come with a tiny chip and embedded antenna able to send data by radio waves -- not only to a clerk -- but perhaps, to someone else nearby.
"Essentially you have data going through the air, and whenever you have data going through the air, somebody else can hear it," said UCLA Engineering professor Rajit Gahd.
Gahd says the designers need to keep up with the threat of hackers as the use of radio frequency ID expands into areas such as financial transactions.
"A lot of effort is being put into keeping people's data secure," says Gahd.
But hacking this new technology is still possible "if they can get the name on the card, the credit card number and the expiration date," said Kena Kai President Geb Masterson.
Masterson's company, Kena Kai, came up with a line of wallets equipped with a special metallic cloth liner that intercepts radio waves.
Masterson recalls that two years ago, researchers at the University of Massachusetts devised a way to read information off cards from several feet away.
"That would be through your clothes, through a normal wallet, through your bag," said Masterson.
The wallets "use our DataSafe Technology that has been Government Certified to meet their standards for an 'Electromagnetically Opaque Sleeve' to protect you against the rising threat of Identity Theft and Tracking," according to the company's website.
"A simple and elegant solution to the security problem," says Gahd.
So far, no significant crime involving RFID has been reported.
Still, Gahd offers this philosophy of digital security: "It's a constant battle, and you have to be ahead as a vendor."
Gahd believes at current encryption levels, it would take enormous computing power to hack an RFID card. Right now it's still easier for an identify thief to find a magnetic strip to swipe.