4.3 Security and Privacy
Many concerns have been expressed over the security and privacy of RFID systems.
Traditional applications, like large-asset tracking, were typically closed systems where tags did not contain sensitive information. Tags on railway cars contained the same information
painted on the side of the cars themselves. However, as more consumer applications are
developed, security, and especially privacy, will become important issues.
Much work has recently focused on issues of RFID security and privacy. Gildas Avoine
maintains a comprehensive bibliography of RFID security and privacy papers [1]. Ari Juels
offers a survey of RFID security and privacy issues in [12]. We refer the reader to these
references for a more comprehensive analysis.
4.3.1Eavesdropping
Perhaps the biggest security concerns in RFID systems are espionage and privacy threats. As
organizations adopt and integrate RFID into their supply chain and inventory control
infrastructure, more and more sensitive data will be entrusted on RFID tags. As these tags
inevitably end up in consumer hands, they could leak sensitive data or be used for tracking
individuals.
An attacker able to eavesdrop from long range could possibly spy on a passive RFID system.
Despite the fact that passive tags have a short operating range, the signal broadcast from the
reader may be monitored from a long distance. This is because the reader signal actually
carries the tag’s power, and thus necessarily must be strong.
A consequence is that a reader communicating with a passive tag in, for instance, a UHF
setting might be monitored from a range up to 100-1000 meters. While this only reveals one
side of a communication protocol, some older protocols actually broadcast sensitive tag data
over the forward channel. Newer specifications, like the EPCglobal class-1 generation-2, take
care to avoid this.
Although short-range eavesdropping requires nearby physical access, it can still be a threat in
many settings. For example, a corporate spy could carry a monitoring device while a retail
store conducts its daily inventory. Alternatively, a spy could simply place bugging devices that
log protocol transmissions.
Espionage need not be passive. Attackers could actively query tags for their contents. Rather
than waiting to eavesdrop on legitimate readers, an active attacker could simply conduct tag
read operations on its own. Active attackers may be easy to detect in a closed retail or
warehouse environment, but may be difficult to detect in the open.