Chameleon RFID and Tracking Prevention

                     Marek Klonowski, Miroslaw Kutylowski, Piotr Syga
                            Wroclaw University of Technology

We propose a method for prevention of tracking RFID tags. We consider 
the model in which the adversary may eavesdrop a large fraction of interactions, 
but not all of them. 

We propose a scheme that we call Chameleon RFID. It is based on dynamic changes 
of identity during each interaction - flipping half of bits at random positions. 
The scheme is not based on any secrets shared by the systems and the tags but on their
continuous interaction. 

We prove privacy properties of the scheme with means of rapid mixing of Markov chains
and provide concrete estimations and experimental evaluation of the rate of convergence 
to the uniform distribution. We also present some specific applications of the method 
proposed. The most important one is leaving traces of unauthorized tag activation. 

Keywords: 
RFID identity management, traceability, privacy, limited view adversary,
Markov chain, rapid mixing, coupling




accepted for RFID Sec Asia'2013