faisal, as this forum foremost is a mailing list, it is fairly bad style to answer a posting which is more than 4 years old without quoting any context.
faisal wrote > but Adobe Acrobat 9/10 allows to add/update a signed pdf and after that > change adobe verify the signature successfully. > > I believe there is something wrong while updating a signed document with > Itext. Have a look at the Adobe Technical White Paper "Adobe Acrobat 9 Digital Signatures, Changes and Improvements" (http://wwwimages.adobe.com/www.adobe.com/content/dam/Adobe/en/devnet/reader/pdfs/readercomp_digitalsignatures.pdf), especially the section "Allowed and disallowed changes". For certified documents it states that allowed changes cannot be more than Adding or editing annotations, Supplying form field values, and Digitally signing; and disallowed changes cannot be less than Adding form fields and Changing page content. For signed but uncertified documents allowed changes are Adding signature fields, Adding or editing annotations, Supplying form field values, and Digitally signing; disallowed changes are Adding form fields other than signature fields and Changing page content. Thus, if "Adobe Acrobat 9/10 allows to add/update a signed pdf" in other ways "and after that change adobe verify the signature successfully", it would have to be considered a bug. This behavior, BTW, is compatible with ISO 32000-1:2008 (http://www.adobe.com/content/dam/Adobe/en/devnet/acrobat/pdfs/PDF32000_2008.pdf). Regards, Michael -- View this message in context: http://itext-general.2136553.n4.nabble.com/Appending-new-pages-to-signed-documents-now-makes-Acrobat-9-and-Reader-9-mark-signature-as-invalid-tp2162558p4657159.html Sent from the iText - General mailing list archive at Nabble.com. ------------------------------------------------------------------------------ LogMeIn Rescue: Anywhere, Anytime Remote support for IT. Free Trial Remotely access PCs and mobile devices and provide instant support Improve your efficiency, and focus on delivering more value-add services Discover what IT Professionals Know. Rescue delivers http://p.sf.net/sfu/logmein_12329d2d _______________________________________________ iText-questions mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/itext-questions iText(R) is a registered trademark of 1T3XT BVBA. Many questions posted to this list can (and will) be answered with a reference to the iText book: http://www.itextpdf.com/book/ Please check the keywords list before you ask for examples: http://itextpdf.com/themes/keywords.php
