Radio frequency identification (RFID) tags are low-cost devices that are used to uniquely identify the objects to which they are attached. Due to the low cost and size that is driving the technology, a tag has limited computational capabilities and resources. This limitation makes the implementation of conventional security protocols to prevent cloning and counterfeiting inefficient. We have uniquely fingerprinted RFID tags based upon their electronic characteristics. We have analyzed three electronic characteristics, minimum power response of the tag measured at multiple frequencies, the backscatter received from the tag when it starts responding at the minimum power and time required to transmit the Electronic Product Code (EPC), Product Code (PC) and Cyclic Redundancy Check (CRC) bits. These characteristics can be used to identify individual RFID tags with high probability. The fingerprint can be used effectively to identify the tags in the future with high probability and to detect counterfeit tags. It can be used as an additional layer of security on any existing tag because it does require any modification or special features on the tag. This mechanism does not increase the cost of the RFID tags because it is independent of the computational capabilities and resources of the RFID tag. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]