-Many RFID tags and contactless smart cards use proprietary security mechanisms for authentication and confidentiality. There are several examples in the literature showing that once these mechanisms have been reverse engineered, their security turns out to be unsatisfactory. Since the use of these tags is quickly expanding to access control and ticketing systems, it is important to independently assess their security. In this paper, we propose three tools for the analysis of RFID protocols. These tools facilitate message eavesdropping and emulation of both tags and readers. The tools focus on high frequency tags but one of them also supports low frequency. These tools are fully programable and allow for quick prototyping, testing and debugging of new RFID protocols. All the software, firmware and hardware we have developed that is described here is open source and open design.