The Enova X-Wall ASIC encrypts with a key obtained via Microwire from a serial EEPROM that stores the key in cleartext, which allows local users with physical access to obtain the key by reading and duplicating an EEPROM that is located on a hardware token, or by sniffing the Microwire bus.
https://exchange.xforce.ibmcloud.com/vulnerabilities/25527
http://www.securityfocus.com/archive/1/429253/100/0/threaded