We had previously done the un-signing part using PDFNet library. But once the documents were un-signed it required the PDF form to be re-enabled through the designer. So basically we are looking for a workaround where we can clear the signatures (that we have already done through PDFNet) but in a way that does not render the PDF file unusable without re-enabling it.
On Wed, Apr 28, 2010 at 9:16 PM, mkl <m...@wir-sind-cool.org> wrote: > > Wasiq Ashfaq, > > > Wasiq Ashfaq wrote: > > We are automating handling of some our PDF documents based on various > > workflows. In certain cases we have to clear the signature from PDF files > > and reject the documents so that they can start over from the starting > > state. Is there a way to clear signatures from signed fields in a way > that > > they can be signed again using Acrobat Reader? Thanks. > > As signing a document essentially means putting a value into a signature > field (i.e. setting its V value) and maybe creating some appearances, this > can be quite easily undone by removing that V value and resetting the > appearances to something neutral. > > Depending on the exact nature of your workflow and the documents, though, > there might be some problems, though. > > E.g. if you have a document with multiple signatures and only want to clear > the newest one, I'm not sure what happens if you do as explained above. > Officially (in Adobe products), signing an empty signature field of an > already signed document is an allowed operation for a number of > certification levels, but "unsigning" as explained above may invalidate > remaining signatures as that is not part of the enumeration of allowed > changes. > > In that case you may revert to the revision before the signed revision > (essentially cutting the document file at the correct position). This, > though, not only removes the signature but also all other changes in that > revision. > > So, the concise answer depends on the nature of the documents you have and > the extend the 'unsigning' may and must have. > > Regards, Michael. > -- > View this message in context: > http://old.nabble.com/Clear-signature-from-a-Signed-field-tp28390524p28390790.html > Sent from the iText - General mailing list archive at Nabble.com. > > > > ------------------------------------------------------------------------------ > _______________________________________________ > iText-questions mailing list > iText-questions@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/itext-questions > > Buy the iText book: http://www.itextpdf.com/book/ > Check the site with examples before you ask questions: > http://www.1t3xt.info/examples/ > You can also search the keywords list: > http://1t3xt.info/tutorials/keywords/ >
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