A method for controlling access to a restricted resource is provided. The method may include receiving, by a cloud server, an identifier from a user device over a long range wireless channel. Further, the method may include comparing the identifier with a plurality of identifiers registered with an access control device. Further, the method may include authenticating the user device based on the comparing and subsequently transmitting a code to the user device upon successful authenticating. Thereafter, the user device may transmit the code to the access control device over a short range wireless channel. Further, the access control device may be configured to provide access to the restricted resource based on receiving of the code. Further, the method may include transmitting the code to the access control device over a long range wireless channel so that the access control device may authenticate the user device.