The invention relates to a method for securing documents that comprises 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. By adopting the above scheme, independent geometric characteristics of the dots can be utilized, and variations of the characteristics of the dots can be measured, so that the variations are integrated into the detection for discriminating an original document from a copy or an illegal print.