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An RFID Primer
Controversy
How would you like it if, for instance, one day you realized your underwear was reporting on your whereabouts? The use of RFID technology has engendered considerable controversy and even product boycotts. The four main privacy concerns regarding RFID are:
- The purchaser of an item will not necessarily be aware of the presence of the tag or be able to remove it;
- The tag can be read at a distance without the knowledge of the individual;
- If a tagged item is paid for by credit card or in conjunction with use of a loyalty card, then it would be possible to tie the unique ID of that item to the identity of the purchaser; and
- Tags create, or are proposed to create, globally unique serial numbers for all products. This creates privacy problems and is unnecessary for most applications.
Most concerns revolve around the fact that RFID tags affixed to products remain functional even after the products have been purchased and taken home, and thus can be used for surveillance, and other nefarious purposes unrelated to their supply chain inventory functions. Although RFID tags are only officially intended for short-distance use, they can be interrogated from greater distances by anyone with a high-gain antenna, potentially allowing the contents of a house to be scanned at a distance. Even short range scanning is a concern if all the items detected are logged in a database every time a person passes a reader, or if it is done for nefarious reasons (e.g., a mugger using a hand-held scanner to obtain an instant assessment of the wealth of potential victims). With permanent RFID serial numbers, an item leaks unexpected information about a person even after disposal; for example, items that are resold, or given away, enable mapping of a person's social network.
Another privacy issue is due to RFID's support for a singulation (anti-collision) protocol. This is the means by which a reader enumerates all the tags responding to it without them mutually interfering. The structure of the most common version of this protocol is such that all but the last bit of each tag's serial number can be deduced by passively eavesdropping on just the reader's part of the protocol. Because of this, whenever RFID tags are near to readers, the distance at which a tag's signal can be eavesdropped is irrelevant; what counts is the distance at which the much more powerful reader can be received. Just how far this can be depends on the type of the reader, but in the extreme case some readers have a maximum power output (4 W) that could be received from tens of kilometers away.
If you would like to know how RFID technology could be implemented in your business contact consulting@realidsystems.com
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