Credit card companies are embedding radio frequency tags (RFID) in credit cards. Since these are transmitters, there’s the possibility of a thief using an RFID sniffer to snag your credit card digits.
Independent researches demonstrated this type of security hole in RFID credit cards back in October.
The credit card companies are eager to expand use of RFID and it will take something going wrong first before they implement stronger security. Until then, consumers have to defend themselves.
One way is to use a RF jammer to block all RF signals around you. Only turn it off when you want to do a transaction.
Lady Ada has a nifty tutorial of making one, assuming you have advanced soldering and circuit bending skills. Barring that, Google yields readymade results. P.S. RF jammers are illegal, see FCC statue inside.
Another way to protect yourself is to not use a credit card with a RFID chip inside, but how long before we don’t have a choice? — BEN POPKEN
UPDATE: This might be a little harder than we thought. We asked Lady Ada if an RF jammer could in fact be used in this way. She says, “it can, however there are multiple RFID frequencies so youd have to pick out VCOs to match.”
RF jammers are illegal in the US and subject to FCC fine.
(m) Harmful interference. Any emission, radiation or induction that endangers the functioning of a radio navigation service or of other safety services or seriously degrades, obstructs or repeatedly interrupts a radiocommunications service operating in accordance with this Chapter.
(p) Kit. Any number of electronic parts, usually provided with a schematic diagram or printed circuit board, which, when assembled in accordance with instructions, results in a device subject to the regulations in this Part, even if additional parts of any type are required to complete assembly.
The operation of transmitters designed to jam or block wireless communications is a violation of the Communications Act of 1934, as amended (“Act”). See 47 U.S.C. Sections 301, 302a, 333. The Act prohibits any person from willfully or maliciously interfering with the radio communications of any station licensed or authorized under the Act or operated by the U.S. government. 47 U.S.C. Section 333. The manufacture, importation, sale or offer for sale, including advertising, of devices designed to block or jam wireless transmissions is prohibited. 47 U.S.C. Section 302a(b). Parties in violation of these provisions may be subject to the penalties set out in 47 U.S.C. Sections 501-510. Fines for a first offense can range as high as $11,000 for each violation or imprisonment for up to one year, and the device used may also be seized and forfeited to the U.S. government. (FCC website)