A wireless apparatus controls physical access through a portal by forward verification of one-time-use codes submitted by a mobile application device. A system forward verifies a single physical access control code upon each successful physical access request. The apparatus sets a flag that triggers an action when a one-time-use code is received out of sequence. The controller receives a plurality of physical access requests from a plurality of mobile application devices. The controller determines for each mobile application device a sequence of access requests comprising at least a first access request and a second access request. Upon authenticating the first access request, the controller writes into storage a forward verification code specific to an immediately subsequent second access request from the same app device. Upon receiving a successor, the controller performs an authentication process by matching the stored forward verification code associated with the predecessor.