author        = {Thomas Plos and Michael Hutter and Martin Feldhofer},
  title         = {Evaluation of Side-Channel Preprocessing Techniques on Cryptographic-Enabled	HF and UHF RFID-Tag Prototypes},
  booktitle     = {Workshop on RFID Security -- RFIDSec 2008, Budapest, Hungary, July 9-11},
  year          = {2008},
  month         = {July},
  editor        = {Sandra Dominikus},
  pages         = {114--127},
  keywords      = {DFA (differential frequency analysis) as preprocessing technique},
  url           = {http://events.iaik.tugraz.at/RFIDSec08}  
  abstract      = {Security-enabled RFID tags become more and more important and integrated in our daily life. While the tags implement cryptographic algorithms that are secure in a mathematical sense, their implementation is not and physical side channels leak information about the secrets. This article focuses on the analysis of electromagnetic side channels and evaluates different preprocessing techniques to increase the attacking performance. In particular, we have applied EM trace-integration techniques as well as Differential Frequency Analysis (DFA). We have investigated HF and UHF-tag prototypes that implement a randomized AES implementation. Our experiments led us to the result that DFA is a powerful technique that allows a fast and time-invariant analysis while misaligned traces due to noise and randomization of operations are of minor concern. We conclude that randomization as a countermeasure against side-channel attacks is a weak protection for RFID tags and has to be combined with other proven countermeasure approaches.}