Signing a pdf may reorganize the internal stucture and never give the same hash. The hash way will never work. You'll have to mark somehow the pdf, maybe with a unique keyword in the pdf info.
Paulo -----Original Message----- From: AndreaC. [mailto:andrea.c...@gmail.com] Sent: Friday, September 30, 2011 10:16 AM To: itext-questions@lists.sourceforge.net Subject: [iText-questions] HASH of PDF strip out of signature Hi all. This is my scenario. At a given time t0 user downloads a pdf file. During document downloading the file HASH is calculated and stored it locally. Note, only the HASH, but not the entire pdf was stored. After that, at t1 time, the same user upload a signed pdf document. Now my problem is that system should calculate an HASH of signed pdf in order to compare it with the stored one. Obviously the t1 HASH should be calculated from the PDF where signature was striped out. So the question is, how can I calculate that t1 time HASH? Thanks in advance, Andrea. p.s. PME -- View this message in context: http://itext-general.2136553.n4.nabble.com/HASH-of-PDF-strip-out-of-signature-tp3859233p3859233.html Sent from the iText - General mailing list archive at Nabble.com. ------------------------------------------------------------------------------ All of the data generated in your IT infrastructure is seriously valuable. Why? It contains a definitive record of application performance, security threats, fraudulent activity, and more. Splunk takes this data and makes sense of it. IT sense. And common sense. http://p.sf.net/sfu/splunk-d2dcopy2 _______________________________________________ iText-questions mailing list iText-questions@lists.sourceforge.net 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 Aviso Legal: Esta mensagem é destinada exclusivamente ao destinatário. Pode conter informação confidencial ou legalmente protegida. A incorrecta transmissão desta mensagem não significa a perca de confidencialidade. Se esta mensagem for recebida por engano, por favor envie-a de volta para o remetente e apague-a do seu sistema de imediato. É proibido a qualquer pessoa que não o destinatário de usar, revelar ou distribuir qualquer parte desta mensagem. Disclaimer: This message is destined exclusively to the intended receiver. It may contain confidential or legally protected information. The incorrect transmission of this message does not mean the loss of its confidentiality. If this message is received by mistake, please send it back to the sender and delete it from your system immediately. It is forbidden to any person who is not the intended receiver to use, distribute or copy any part of this message. ------------------------------------------------------------------------------ All of the data generated in your IT infrastructure is seriously valuable. Why? It contains a definitive record of application performance, security threats, fraudulent activity, and more. Splunk takes this data and makes sense of it. IT sense. And common sense. http://p.sf.net/sfu/splunk-d2dcopy2 _______________________________________________ iText-questions mailing list iText-questions@lists.sourceforge.net 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
