1. A method for embedding a digital watermark w into textual and/or vector graphics documents of electronic and/or hard-copy form, based on the modulation of luminance or grayscale values, of color values, and/or of halftone patterns of characters and/or of vector elements, the method comprising the steps of (a) encoding a digital message m, resulting into a codeword c; spatially allocating the codeword c, resulting into a watermark signal w suitable for text and/or vector graphics modulation, (b) parsing the original input document in electronic format x in order to isolate all its components, (c) selecting text and/or vector graphics components x text which will carry the watermark w and parsing components x text in order to select single entities or elements to use to encode individual w symbols; and keeping the remaining non selected components x non-text for later document recomposition, (d) modulating the grayscale attributes, the color attributes and/or the halftone pattern attributes of the selected elements in the selected text and/or vector graphics components x text , (e) recomposing the document from the marked version of selected components x text and the remaining components x non-text , resulting into a watermarked document y, which can be stored, distributed, and/or used in electronic form as electronic document {hacek over (y)} a or in printed form as hard copy document {hacek over (y)} b .
1. A method for embedding a digital watermark w into textual and/or vector graphics documents of electronic and/or hard-copy form, based on the modulation of luminance or grayscale values, of color values, and/or of halftone patterns of characters and/or of vector elements, the method comprising the steps of (a) encoding a digital message m, resulting into a codeword c; spatially allocating the codeword c, resulting into a watermark signal w suitable for text and/or vector graphics modulation, (b) parsing the original input document in electronic format x in order to isolate all its components, (c) selecting text and/or vector graphics components x text which will carry the watermark w and parsing components x text in order to select single entities or elements to use to encode individual w symbols; and keeping the remaining non selected components x non-text for later document recomposition, (d) modulating the grayscale attributes, the color attributes and/or the halftone pattern attributes of the selected elements in the selected text and/or vector graphics components x text , (e) recomposing the document from the marked version of selected components x text and the remaining components x non-text , resulting into a watermarked document y, which can be stored, distributed, and/or used in electronic form as electronic document {hacek over (y)} a or in printed form as hard copy document {hacek over (y)} b . 4. The method of claim 1 wherein said selected components for watermarking are text components and/or vector graphics components; wherein elements suitable for modulation are single characters, parts or zones of single characters, groups of characters, vector graphics elements and/or known parts/zones of them; wherein elements used for marking are selected based on any criteria in prevision of future accurate detection.