Access control

An access control system, comprising:

• a near field communication (NFC) tag configured to wirelessly provide a data value;
• an access point comprising a lock and a mechanism to control a state of the lock;
• a controller for the access point that is configured to transmit instructions to the access point to change the state of the lock, wherein the controller further includes a first local wireless network interface and a first data repository, wherein the first data repository is configured to locally store authentication data for authorized users;
• and
• a mobile device that includes an NFC reader, a second local wireless network interface, and a second data repository that stores authentication data for a corresponding user, wherein the mobile device is configured to:
• receive, using the NFC reader, the data value from the NFC tag;
• interpret the data value received from the NFC tag;
• generate, based on the interpretation of the data value, a wireless access request, wherein the wireless access request includes the controller as a recipient and the authentication data;
• and
• transmit, using the second local wireless network interface, the wireless access request to the controller over a local wireless network connection with the controller;
• wherein the controller is configured to evaluate the authentication data received in the wireless access request received from the mobile device against the locally stored authentication data and, based on the evaluation, to send a control signal to the access point to modify a state of the lock.