Metatron Citadel/Slate

Metatron Slate is a brand of ruggedised pin-pad card reader developed by Metatron Access Control for military and intelligence applications. It is designed for integration into the wider Metatron Citadel system. It features the full range of Citadel security countermeasures, including a fully encapsulating tamper mesh and resistance to gunfire and explosions. It is also hermetically sealed, dust and liquid proof, and can operate in extreme heat, extreme cold, and absolute vacuum. The unit features a physical tactile keypad which randomises its digits on each attempt and limits the viewing angle of the digits to a tight radius. The keypad is designed to operate in all conditions and be usable even by operators in exosuit. The panel also features a small non-touch screen at the top which displays status messages and alarms.

Mechanism

All elements of the Slate reader are cryptographically bound. The process is first initiated by touching a valid card to the reader. A secure channel is then established between the reader and the card, which turns on the display and enables and randomises the keypad. The reader is either controlled by the Door Control Unit (DCU) or directly by the Citadel controller (located inside the secure perimeter).

After the PIN has been entered, it is directly sent to the card, which validates it. If the card reports it is not valid, the reader locks itself down and sends a signal to the controller to trigger an invalid PIN alarm; the card also increments its own internal counter, which if exceeded, will make the card permanently deactivate itself. If it is valid, the card cryptographically signs a token generated by the reader which is sent to the controller. The PIN is never sent to the controller. The controller cryptographically verifies both the reader and card signature on the token, then either approves or denies the request depending on its own logic.