A system for identifying a key to a lock. The system uses a simple scanner. Within the scanner, a plate is illuminated by at least one LED. Opposite the plate is positioned a matrix of photodetectors. The plate and the matrix of photodetectors are separated by a slot that is sized to receive the key. The matrix of photodetectors generates an electronic signal that is indicative of light from the plate that passes across the key in the slot. A memory is provided that stores known key signals. A processor is provided that compares the newly generated electronic signal to the known key signals in the memory to find a match. A display is provided for displaying information about which the key signals from memory is a match. In this manner, a person can identify the key.