Distributed one-time-use entry code generation for physical access control method of operation and mobile systems
A physical access control system enables acceptable portal entry codes upon receiving each physical access request by operating on the elapsed time from a previous physical access request to generate a temporal credential. The controller receives a plurality of physical access requests from a plurality of mobile application devices. Upon authenticating the first access request, the controller eliminates repetition from the space of acceptable successor requests from each mobile application device. Monotonic nonces advance the range of temporal code matches. Entry code generation is decentralized to distributed application devices and is inherently unknowable until a successor access request is initiated by the same application device.
1. A method of operation of a wireless physical access control system, the method comprising:
transmitting, by a panel, a beacon packet containing a reader identifier;
receiving, by a mobile device, the beacon packet;
in response to receiving the beacon packet:
retrieving from storage, a user identifier, a door identifier and a user credential;
determining a timestamp from a system clock;
determining a current time interval between a timestamp corresponding to a previous access request to a current timestamp;
hashing the user identifier, the user credential, the door identifier and the current time interval into a current access request; and
transmitting the current access request;
receiving, by the panel, the current access request;
parsing the current access request for the user identifier, the door identifier, the user credential and the current time interval;
determining one or more previous time intervals associated with the mobile device; and
determining whether the current time interval matches at least one of the one or more previous time intervals; and
if the current time interval matches at least one of the one or more previous time intervals, actuating a door corresponding to the door identifier; or
if the current time interval does not match any of the one or more previous time intervals, recording failure of the current access request.
2. The method of claim 1 , further comprising
triggering a nonce circuit when the current access request matches at least one of the one or more previous time intervals.