30. The method according to claim 29 , wherein obtaining includes receiving.
29. A method for verifying matching content between a plurality of text documents implemented with a numerical computation device, comprising: electronically obtaining an image document derived from a first electronic text document; electronically obtaining a first authentication signature generated from the first electronic text document; transforming the image document to a second electronic text document; generating a second authentication signature from the second electronic text document; and determining if the first and second authentication signatures meet a match criterion.