Detecting RFID tag and inhibiting skimming
A method of detecting an RFID tag includes transmitting a bait RFID read signal at a bait power level and a simulated response signal at a simulated-response power level. A selected reader frequency is monitored for a selected detection time. A skimmer is determined to be present if a skimmer RFID read signal is detected during that time. If a skimmer is not determined to be present, multiple read signals are transmitted sequentially, each signal at a respective read power level. At least one of the read power levels is lower than the bait power level, at least one of the read power levels is lower than the simulated-response power level, and at least two of the read power levels are different from each other. A selected response frequency for a tag is monitored for a response from an RFID tag.
1. A method of detecting an RFID tag, comprising:
transmitting a bait RFID read signal at a bait power level using an RFID reader;
transmitting a simulated response signal at a simulated-response power level;
a skimmer-detection step of automatically monitoring a selected reader frequency for a selected detection time using a controller, wherein a skimmer is determined to be present if a skimmer RFID read signal is detected during the selected detection time;
if a skimmer is not determined to be present, transmitting multiple read signals sequentially;
monitoring a selected response frequency for a tag response from an RFID tag, wherein the tag is detected if the tag response is received; and
transmitting each read signal at a respective read power level and wherein at least two of the read power levels are different from each other to indicate that the reader is an authorized reader and receiving the tag response only if the reader is an authorized reader and at least one of the read power levels is lower than the bait power level and at least one of the read power levels is lower than the simulated-response power level.
2. The method according to claim 1 , wherein each read signal after a first-transmitted one of the read signals is transmitted at a selected time interval after the preceding read signal to indicate that the reader is an authorized reader and receiving the tag response only if the reader is an authorized reader.
3. The method according to claim 1 , wherein each read signal includes respective authorization data.
4. The method according to claim 1 , wherein the skimmer-detection step further includes monitoring the selected response frequency for the selected detection time.
5. The method according to claim 1 , further including, after transmitting one of the read signals, monitoring a selected second reader frequency for a selected second detection time, wherein a skimmer is determined to be present if a skimmer RFID read signal is detected during the selected second detection time.
6. The method according to claim 5 , wherein the selected second reader frequency is different than the selected reader frequency and the selected second detection time is different than the selected detection time.
7. The method according to claim 1 , further including, after transmitting one of the read signals, transmitting a second simulated response signal.
8. The method according to claim 7 , further including, after transmitting the second simulated response signal, monitoring a selected second reader frequency for a selected second detection time, wherein a skimmer is determined to be present if a skimmer RFID read signal is detected during the selected second detection time.
9. The method according to claim 8 , wherein the selected second reader frequency is different than the selected reader frequency and the selected second detection time is different than the selected detection time.
10. The method according to claim 1 , further including, if a skimmer is determined to be present, reporting an alert, collecting forensic evidence, labeling the RFID tag as corrupt, deactivating the RFID tag, or storing an indication of the skimming in the RFID tag or a memory.
11. The method according to claim 1 ,
wherein each read signal has a signal characteristic selected from the group consisting of a received power level of the respective read signal, the time interval between the respective read signal and a preceding or following read signal, and identification data included in the respective read signal, whereby each characteristic has a respective type of “power level,” “time interval,” or “identification data,” respectively,
so that the sequential transmission of the multiple read signals transmits an authorization sequence of signal characteristics.
12. The method according to claim 11 , further including selecting a first one of the read signal characteristics and selecting a second one of the read signal characteristics, the signal characteristics each having a type and wherein the type of the first selected one of the read signal characteristics is different than the type of the second selected one of the read signal characteristics.