Post Oak AWAM Bluetooth Reader Traffic System does not use a sufficient source of entropy for private keys, which makes it easier for man-in-the-middle attackers to spoof a device by predicting a key value.
https://www.cisa.gov/news-events/ics-advisories/icsa-12-335-01
http://www.us-cert.gov/control_systems/pdf/ICSA-12-335-01.pdf