Method of and apparatus for embedding data into an electronic document

摘要

There is described a method of and apparatus for embedding data into an electronic document by modulating the spaces between words. In the method of coding an electronic text document (1), the length of a space (pi) preceding a word (2i) in a line of text data forming part of an electronic document (1) relative to the length of a space (si) following the word (2i) is modulated with the value of a bit of signature data (31). The signature data (31) is thus embedded into the text data (33) of the electronic document (1), and is thus not easily discernible by unauthorised readers. <IMAGE>