Most people are aware there are two types of RFID tags, active tags (ones that contain a power source of some kind) and passive tags (ones that are powered by the RF field).
I'd like to know if choosing one type or the other provides a security advantage? Does the ability to power passive tags only via RF field mean that it is harder to implement secure designs? Are there any other security concerns I should consider when choosing RFID systems?
Network bandwidth is a scarce resource in RFID protocols.
Active tags have a double edge sword when it comes to security. For one they are able to support more bandwidth and therefore larger key sizes. The "problem" is that active tags also have a longer range, and there for an attacker further away is able to obtain a challenge response. Passive tags have a shorter range, and are limited in the cryptographic algorithms they are able to use...
So what is your implantation? Ideally you would have a faraday cage to protect your active tags when they are not in use.
