urnstile, which allows access after the reader checks the validity of the ticket. Each NFC device has the potential to replace a wallet full of credit cards, which is a liability if it falls into the wrong hands. NFC proponents are quick to note that a lost or stolen mobile phone can be disabled with a single call to the ser- vice provider, but canceling a wallet full of credit and bank cards requires at least an hour. One of the most important things to be aware of is that NFC security is a matter of accepting or not accepting a message from another device. Users must therefore constantly be aware of the status of their devices, and know, for example, whether they are configured to automatically connect with nearby NFC devices. There are also some threats unique to NFC, as well as opportunities for clever thieves. For example, as RFID chips and readers become more pervasive, we can imagine a new technique emerging, something being referred to as billboard phish- ing, where the impersonator could possibly paste posters, with embedded phony RFID chips, over kiosks, posters, or turnstiles. In this case, how is the user to know whether what they are touching is fake or legitimate? As with RFID technol- ogy, security professionals need to help shape the security policies and protocols that might affect device authentication and other issues. To this end, the NFC Forum has formed a security workgroup to develop industry standards. NFC technology is currently being used extensively in Asia and the Pacific, and it is being used less in Europe and even less in the United States. However, we can expect to see NFC expand rapidly, especially in payment transaction scenarios and public transportation. This page intentionally left blank Chapter Emerging Wireless Applications Realizing the utopian visions of the wireless world requires continued innovation, and indeed, the innovation occurring in the wireless arena today is nothing short of amazing. Throughout the long history of radio, wireless has been largely con- cerned wi