RFID systems makes it possible for a server to identify known tags in wireless settings. As they become more and more pervasive, people privacy is more and more threatened. In this talk, we list a few models for privacy in RFID and compare them. We review a few protocols. We further show that strong privacy mandates the use of public-key cryptography. Finally, we present a new cryptosystem which is dedicated to tiny hardware and which can be used to design secure RFID systems achieving strong privacy.