Abstract: The method for authenticating a code with geometric areas whose shapes and/or colors vary according to a message includes: a step (115) in which the code with variable geometric areas is generated, according to a message, to provide geometric areas; a step (120 to 130) in which a digital authentication code is generated to provide numeric values and a step (135) in which an image of the geometric code areas is formed, including a part of the digital authentication code in at least some of its geometric areas and/or in at least one space between geometric areas.

Abstract: A process for securing a document including a step of printing a distribution of dots on said document, said printing, as a result of unanticipated unknowns in printing, causing an unpredictable variation, dot by dot, of at least one geometric characteristic of the printed dots and prior to said print step, a step generating said distribution of dots so that at least half the dots of said distribution are not laterally juxtaposed to four other dots of said dot distribution, and at least one dimension of at least one part of the dots of said distribution of dots is of the same order of magnitude as the average for the absolute value of said unpredictable variation. In embodiments, during the step generating the dot distribution, more than half the dots do not touch any other dot of said distribution.