Distributed one-time-use entry code generation for physical access control method of operation and mobile systems

A method of physical access control of a mobile device by a physical access system including a server in communication with mobile devices, the method comprising:

• at a panel controlling a door actuator:
• transmitting a beacon packet containing a reader identifier;
• at a mobile device:
• storing, in non-transitory storage, a user identifier, a user access credential and a first timestamp associated with a first access request;
• receiving the reader identifier;
• retrieving, from the non-transitory storage, the user identifier and the user credential;
• determining an interval between the first timestamp and a second timestamp read from a system clock of the mobile device;
• hashing the door identifier, the user credential, and the interval;
• constructing a second access request packet from a result of the hashing, the door identifier and the user identifier;
• transmitting the second access request packet to the panel;
• at the panel:
• receiving the access request packet from the mobile device;
• parsing the access request packet for the user identifier and the door identifier;
• retrieving, from a memory, the user credential associated with the user identification and the door identifier;
• determining a plurality of intervals for the mobile device from the timestamp;
• determining a plurality of acceptable intervals for the user credential;
• and
• actuating a portal when any access request contains one of the plurality of acceptable intervals.