The presently claimed invention relates generally to gaining access to secure systems. One claim recites an apparatus including: an image or video sensor for capturing image or video data; and a multi-purpose computer processor configured to: decode machine-readable information encoded in captured image or video data representing a plurality of physical objects, each instance of machine-readable information includes identifying information; determine an order in which the physical objects are presented to the image or video sensor for evaluation via the identifying information; and comparing the order to a predetermined sequence to determine whether to allow access to a remotely located computerized system. The apparatus may be housed, e.g., in a cell phone. Other combinations and claims are provided as well.