A system for authenticating the user of a computing device comprises an authorized user directory. Each record is uniquely associated with an authorized user and includes at least a computing device ID value that is a globally unique value assigned to the authorized user's computing device, a group of unique depictions such as photographs, an identification of a key depiction. Portions of each image form fiducials recognizable by the user. The record further includes trace pattern verification data representing continuous trace strokes between pairs of the fiducials within the key depiction. To authenticate, the group of images are displayed to the user. The user must first select the key image and secondly trace continuous trace strokes between the pairs of fiducials to match the trace pattern verification data.