A thief cannot scan "conventional" credit cards through the walls of a purse. He can, however, target a new generation of credit cards that use "hands-free" RFID technology. Designed to save consumers time at the checkout counter, hands-free credit cards can be read by the register from a range up to 18 inches.

Each hands-free credit card contains a small device called a "passive RFID tag." This tag consists of a coil of flattened wire connected to a tiny electrical circuit. When a magnetic field of a radio waves strikes the coil, it induces an electrical current within the coil's metal. This electrical energy is collected as voltage inside the card's circuit. Once a certain amount of voltage has been collected, the energy is released into a separate part of the circuit where it is converted into a pattern of electrical pulses. Note: each card produces its own, unique pulse pattern, which contains coded account information.

When this pulse pattern flows back through the coil, it causes the coil to emit a radio wave containing the exact same pattern. Finally, this radio wave is received by a specially-calibrated antenna located inside the register's scanner.