Hacking RFID Tags Is Easier Than You Think

The RFID output that the Arduino gets is a 10-digit hexadecimal. With that in hand, Brown said it’s simple to replicate the remotely stolen information using a Proxmark device.

The unfortunate reality, according to Brown, is that with most of the building security badges that are running at 125KHz, there is no secure authentication mechanism.

via Hacking RFID Tags Is Easier Than You Think: Black Hat.