If you simply take the modification date and ID entries used in your first phase (when you generated the hash) and identically recreate that state later persuading iText to use the same values, you should be out of trouble for now.
Obviously you should take care not to accidentally apply different signatures to the same base document using the identical ID. Two PDF files with the same actual ID should definitely be identical. If you generate the ID yourself instead of using an ID generated by iText please be aware of the structure of the ID array as documented in the PDF spec. You should not, on the other other, be too sure that identical recreation of a document state will remain possible in all later iText releases. E.g. it always is possible that some coming change will unintentionally make the order of addition of PDF objects to the base document depend on some external uncontrolable semi-random state making it impossible for you to identically recreate the PDF for signature insertion. Regards, Michael. -----Original Message----- From: amarianoelaide [mailto:amari...@elaide.com] Sent: Thursday, April 02, 2009 2:17 PM To: itext-questions@lists.sourceforge.net Subject: Re: [iText-questions] Hash computation problem Thank you for the ultra-complete answer. But what about if I don't remove ModDate and fileID but simply modify the code to pass them to the library? Is it possible, and do I avoid those problems you pointed out? -- View this message in context: http://www.nabble.com/Hash-computation-problem-tp22801988p22846530.html -- Neu: GMX FreeDSL Komplettanschluss mit DSL 6.000 Flatrate + Telefonanschluss für nur 17,95 Euro/mtl.!* http://dsl.gmx.de/?ac=OM.AD.PD003K11308T4569a ------------------------------------------------------------------------------ _______________________________________________ iText-questions mailing list iText-questions@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/itext-questions Buy the iText book: http://www.1t3xt.com/docs/book.php
