1. A method for characterizing an unpowered integrated circuit comprising: obtaining a first data set by coupling a first RF-input stimulus signal to each first pin pair of a known integrated circuit having a plurality of first pin pairs, and, for each coupling, measuring and recording a first RF energy reflected back from the known integrated circuit on the first RF-input stimulus signal and a plurality of first RF energy levels at all other first pin pairs of the plurality of first pin pairs; creating a fingerprint for the known integrated circuit by collecting, analyzing, and correlating the first data set; providing a test device having a backside and including a plurality of second pin pairs, wherein the test device is the unpowered integrated circuit; obtaining a second data set by coupling a second RF-input stimulus signal to each second pin pair of the plurality of second pin pairs and for each coupling measuring and recording a second RF energy reflected back from the test device on the second RF-input stimulus signal and measuring and recording a plurality of second RF energy levels at all other second pin pairs of the plurality of second pin pairs; creating a test device fingerprint for the test device by collecting, analyzing, and correlating the second data set; and comparing the fingerprint to the test device fingerprint to determine if the test device has been modified to differ from a configuration of the known integrated circuit.