1. An image processing apparatus for processing paper fingerprint information that represents a fiber pattern unique to a paper sheet, comprising: a scanner unit adapted to scan the paper fingerprint information that represents the fiber pattern unique to a paper sheet; an embedding unit adapted to embed the paper fingerprint information and position information of the paper fingerprint information at two corners as cater-cornered positions on the paper sheet; and an extraction unit adapted to extract the paper fingerprint information based on the embedded position information.