An authentication device may provide an authentication code to a third party device. The third party device may provide a third party service to which a client device has requested access. The authentication device may receive the authentication code from a mobile device that is different from the client device. The authentication device may determine a third party device identifier included in the authentication code. The third party device identifier may identify the third party device that provides the third party service. The authentication device may determine a transaction identifier included in the authentication code. The authentication device may selectively provide the transaction identifier to the third party device, identified by the third party device identifier, to cause the third party device to selectively permit the client device to access the third party service.