An increasing number of credit cards now contain a tiny wireless computer chip and antenna based on RFID (radio frequency identification) and contactless smart card technology. The RFID-enabled credit cards permit contactless payments that are fast, easy and often more reliable than magnetic stripe card transactions, and only physical proximity (rather than contact) is required between this type of credit card and the reader. An estimated 20 million RFID-enabled credit cards and 150,000 vendor readers are already deployed in the U.S. (Bray, 2006). According to Visa USA, “This has been the fastest acceptance of new payment technology in the history of the industry” (Bray, 2006).