Pam_blue is a dynamically loadable binary object for the pam security framework in linux. it is presented as an extension for the common pam modules, gives the user the ability for authenticate via a bluetooth-compatible device like a cell phone or other bluetooth dongles (e.g. epox-presenter). due to the fact that a whole part of the bluetooth stack is implemented in hardware-side it is relatively difficult to change the bluetooth hardware mac address which makes this module more secure.