From cell phones to ID cards, the use of RFID (radio frequency identification) and "contactless" smart card technology (debit and credit cards read by readers without being swiped in them) has been increasingly popular in recent years. The underlying technologies are similar but have important distinctions, which are often confusing to travelers.

RFID tags have a wide range of uses, from inventory control to user identification, and both government and industry are relying on them as everything from unlocking your car door to border control goes high tech. They broadcast unencrypted information as far as 30 feet. Contactless smart cards are an evolution of the technology - RF-enabled contactless smart card technology contains a computer with security software and wireless communication for very short distances of an inch or two to protect the privacy and safety of the data.  It uses advanced digital security techniques not possible with RFID.

These new uses of technology are generally a good thing - a quick wave of a smart card at checkout, using your phone to pay for public transportation, passports that are unable to be duplicated or altered.  But convenience and technology often have a darker side.

Due to different cards having varying security standards, the possibility exists that by "skimming" information (accessing data in an unauthorized fashion) from a variety of cards a person is carrying, someone can put enough information together to steal your identity. How so? As we'll see, an overseas traveler can easily have an e-passport or passport card, several contactless credit cards, even a public transportation card, all with varying forms of security. Add in RFID enabled cell phones, which people often fill up with personal information, and you have a recipe for trouble.

Perhaps even more disconcerting, while authorities and experts insist these cards and IDs are safe, few are willing to address the fact that RFID allows people to be tracked. This has wide implications for personal privacy, not to mention applications for law enforcement and government tracking.