How RFID is Improving Short-Range Communication,

The precedence of RFID is that it does not require direct contact or line-of-sight scanning. An RFID system consists of three components: an antenna and transceiver (often combined into one reader) and a transponder (the tag). The antenna uses radio frequency waves to transmit a signal that activates the transponder. When activated, the tag transmits data back to the antenna. The data is used to notify a programmable logic controller that an action should occur. The action could be as simple as raising an access gate or as complicated as interfacing with a database to carry out a monetary transaction. Low-frequency RFID systems (30 KHz to 500 KHz) have short transmission ranges (generally less than six feet). High-frequency RFID systems (850 MHz to 950 MHz and 2.4 GHz to 2.5 GHz) offer longer transmission ranges (more than 90 feet). In general, the higher the frequency, the more expensive the system. RFID is sometimes called dedicated short range communication (DSRC).

28.2 RFID Primer
With all the potential doomsday scenarios that critics like to associate with the use of RFID systems, why would anybody even consider doing this? This is because RFID systems offer three distinct advantages over traditional identification systems:
1. Automation. While optical bar codes require a line of sight for readout, i.e., either careful orientation of tagged goods with respect to the reader, or manual intervention, RFID tags promise unsupervised readouts. This increases the level of automation possible, as tagged items do not need precise orientation during the readout process.
2. Identification. RFID tags also offer a much higher information density than bar codes, allowing manufacturers and vendors not only to store a generic product id...

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...l ID) in order to unlock it again. However, as a single fixed Meta ID would not solve the problem of location privacy, i.e., unwanted tracking and profiling, these Meta IDs would need to change periodically, e.g., upon each read request. But with an ever-changing ID, even legitimate readers might have a hard time figuring out the correct password of a tag in order to unlock it. This implies the need for significant data management structures to keep track of one’s items and their current Meta IDs – a requirement that questions the practicability of such a scheme. Even if one assumes a single password for all of one’s personal items (e.g., a smart phone furnishes a key to the supermarket’s point-of-sale device during checkout), the associated key management problem would still be significant (imagine buying things for other people, or forgetting your phone at home).