Abstract: The present invention relates to a method for deterring fraud with documents having monetary value such as a PVC substrate having a signature location on the substrate. In the method, a supporting ink layer 2 including a pigment and containing a product that assures it a certain porosity with respect to the substrate is deposited on the signature location; then a transparent, porous varnish layer 3 including a dissolved powder enabling a fluorescence of the desired color to be obtained under ultraviolet light is deposited on certain zones of the first ink layer 2; next a filigree pattern is printed in zones of either the first ink layer 2 or the varnish layer 3, using a silkscreening process and a second pigmented vinyl ink 4. The signature or identifying mark of the owner of the document is executed using a felt-tip pen having an indelible ink, of the type which is indelible to a product such as that sold under the mark "CORRECTOR".

Abstract: A device enabling blocking of a slot formed in a wall separating two medi and the free access, in the open position, from one medium to the other, of a flat object, characterized in that it comprises a cylindrical element pivoted about its axis placed in front of the said slot, having an elongated radial opening therethrough, the said cylinder being provided with a drive member for rotating the same and a position control for stopping said cylinder in predetermined positions.