It won't work. You may put as many signers as you want in the PKCS7 but the PDF specification only accepts a single signer.
Paulo > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On > Behalf Of drivexcite > Sent: Tuesday, September 09, 2008 3:52 PM > To: [email protected] > Subject: Re: [iText-questions] PDF Digital Signature: > precalculated signature and hash. > > > Please, let us know your results! > Thanks. > > > Andreas Kuehne-2 wrote: > > > > Hi ! > > > > What's the problem with co-signing ? > > PKCS7 supports it from the beginning ( guess back in the > 90ies ). You can > > add signers to the signature as you like. You can add new > signers to a > > given signature without breaking the document ( if the > signature space > > within the PDF is big enough, because it grows with every > new signer ). > > > > I'm not sure whether Acrobat supprts co-signing, but I'll > give it a try .. > > > > Greetings > > > > Andreas > > > > > > > > ----- Original Message ---- > > From: Leonard Rosenthol <[EMAIL PROTECTED]> > > To: Post all your questions about iText here > > <[email protected]> > > Sent: Friday, September 5, 2008 7:34:57 PM > > Subject: Re: [iText-questions] PDF Digital Signature: precalculated > > signature and hash. > > > > PDF signatures do not work the way you wish. > > > > The concept of "parallel signatures" that you describe is one that > > various standards bodies are currently investigating for > the future of > > PDF. > > > > Leonard > > > > > > On Sep 5, 2008, at 1:27 PM, drivexcite wrote: > > > >> > >> Hi everyone, > >> > >> I have a static PDF document that needs to be signed by different > >> users; the > >> document cannot be modified until all the user's signatures are > >> collected. > >> > >> Unfortunately, all the examples of multiple signatures I've seen so > >> far, > >> somehow change the state of the source document, and as a result, > >> calculating the hash multiple times using > >> PDfSignatureAppearance.getRangeStream() does not produce the same > >> value. > >> Apparently, the first signature protects the original document, the > >> second > >> signature protects the first signed version, and so on. > >> > >> I want all signatures protects the original document. > >> > >> So my questions are: > >> 1.- It is possible to calculate a digital signature on > a PDF document > >> without modifying it? What stream of bytes can I use to > obtain this > >> result? > >> (I'm sure getRangeStream() is not the answer) > >> 2.- In the example "How to sign with an external > signature and a > >> standard > >> filter" I noticed the hash is calculated using > getRangeStream(), BUT > >> the > >> signature is calculated using the hash! Is that right? I'm not a > >> security > >> expert but I think the signature should be calculated using the > >> source data, > >> not the hash. > >> 3.- Once the hashes and signatures has been calculated over the > >> source > >> data, how can I create a signed PDF version? > >> > >> I found a similar > >> > http://www.nabble.com/sign-a-pdf-document-using-external-hash- > and-signature-tt8747172.html#a8747172 > >> question on the forum, but it remains unanswered. > >> > >> Thanks! > >> Tonatihu Díaz. > >> -- > >> View this message in context: > >> > http://www.nabble.com/PDF-Digital-Signature%3A-precalculated-s > ignature-and-hash.-tp19336006p19336006.html > >> Sent from the iText - General mailing list archive at Nabble.com. 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. ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ iText-questions mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/itext-questions Buy the iText book: http://www.1t3xt.com/docs/book.php
