Rui, the reason why I am surprised (and thus interested) that after some of your manipulations Adobe products still say the signatures are valid, is that Adobe states:
>>>> Allowed actions for signed but uncertified documents When a document is first signed, the set of allowed actions by default is set to those specified in the following table. Applying disallowed changes to a signed document invalidates the signatures on that document. Allowed • Adding signature fields (see Limitations on adding signature fields to signed but uncertified documents) • Adding or editing annotations • Supplying form field values • Digitally signing Disallowed • Adding form fields other than signature fields • Changing page content <<<< http://www.adobe.com/devnet/reader/articles/reader_compatibility/readercomp_digitalsignatures.pdf (This set of allowed changes also is the biggest available for certified documents.) The changes you mention seem definitely to be of the "Changing page content" type... Thus, even if some of your changes leave the signatures valid according to current Reader versions, I would not count on that being still true after the next Reader updates. Regards, Michael. -----Original Message----- From: rui fernandes [mailto:rjmfernan...@gmail.com] Sent: Thursday, April 16, 2009 7:32 PM To: itext-questions@lists.sourceforge.net Subject: Re: [iText-questions] Signature gets corrupted when editing aftersign Ok to be exact, they don't substitute pages, they are not so radical. They just scale the original content and put the image bellow. More correct behaviour impossible. It looks like this is too much enough for adobe not to recognize all the info on the original digital signature. Even for its last version. I think is wrong, but they probably have their reasons whatever they be. Maybe if they were just as radical as I thought they were adobe would think is ok, who knows. 2009/4/16 rui fernandes <rjmfernan...@gmail.com>: > Ok Michael. For you to know, I saw it happened still in v9.... It's > not on my project, but another one. They are more radical than me, > it's not just an image added, is a page replaced with a scaled image > of the original page, and an image added bellow. Then they end up > still on same issue even with adobe reader 9. So I guess this is > useful for you to see the limitation/level of flexibility added on the > new version by adobe on signed pdf edition from the point of view of > the digital signature's info. Hope it helps. > > I will try to think with the other project's people in an alternative > to get them closer to what I do, and farer from their actual more > radical approach. > Toomany people trying too hard on pdf and electronic signatures... > -- Un saludo, Rui -- Neu: GMX FreeDSL Komplettanschluss mit DSL 6.000 Flatrate + Telefonanschluss für nur 17,95 Euro/mtl.!* http://dslspecial.gmx.de/freedsl-surfflat/?ac=OM.AD.PD003K11308T4569a ------------------------------------------------------------------------------ Stay on top of everything new and different, both inside and around Java (TM) technology - register by April 22, and save $200 on the JavaOne (SM) conference, June 2-5, 2009, San Francisco. 300 plus technical and hands-on sessions. Register today. Use priority code J9JMT32. http://p.sf.net/sfu/p _______________________________________________ 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
