A method provides device access security via use of periodically changing Quick Response (QR) codes. The method includes: generating (706) a first authentication QR code and assigning (708) the generated QR code as the current authentication mechanism for accessing the device. Contemporaneously with the generation of the QR code, at least one QR code validity parameter is established (710) to define when access to the device can be provided to a second device that provides the correct authentication QR code along with the access request. The method includes, in response to a pre-defined trigger (712) of the QR code validity parameter: generating (704) a new authentication QR code, different from a previously generated authentication QR code; assigning (708) the new authentication QR code as the current authentication mechanism for accessing the device; and enabling access to the first device to only second devices that provide the current authentication QR code.