Fecha de publicación: 08/08/2019 Fuente: Wipo "digitalization" Some implementations may include a computer-implemented method for applying at least two digital watermarks to a digital document, the method including: receiving a digital document comprising visual contents; generating a first digital watermark to be visually presented at a first time point; generating a second digital watermark to be visually presented at a second time point, the second digital watermark being different from the first digital watermark and the second time point being different from the first time point; and applying both the first digital watermark and second digital watermark to the digital document t.