Privacy Protection in Dynamic Systems Based on RFID Tags

We propose a solution for privacy problems regarding use of electronic identification tags such as RFID's. In our scheme the ID tag changes at random driven by its internal circuitry during each activation. The changes are small enough so that the legitimate system can recognize the tag and register the modified ID for the next activation. On the other hand, after a certain number of activations the new ID cannot be linked with the original one. We provide a rigid mathematical analysis of security of this unlinkability property.