METHOD AND SYSTEM FOR AUTHENTICATING A SECURE DOCUMENT

The method of automatically authenticating a document having a label-forming portion comprises the following steps: a) printing an authentic label having optically-variable elements; b) photographing the authentic label to create a first reference image; c) calculating and storing a reference digital fingerprint of the label; d) photographing a label for verification successively in first lighting conditions and in second lighting conditions that are essentially different from the first lighting conditions in order to create first and second verification images, by using a camera having a communications unit, a memory unit, and a calculation unit; e) verifying the optically-variable nature of said elements from the first and second verification images and calculating a verification digital fingerprint for the label that is to be verified; and f) comparing the verification digital fingerprint with the corresponding reference digital fingerprint, calculating the distance between these two digital fingerprints, and comparing the distance with a predetermined threshold.