You can put whatever you want in the digital signature payload and in the signature dictionary. I don't see any issue here. If you add the signature in append mode you can even get the original PDF before signing.
Paulo ----- Original Message ----- From: "Martin Paljak" <[EMAIL PROTECTED]> To: "Post all your questions about iText here" <itext-questions@lists.sourceforge.net> Sent: Tuesday, August 28, 2007 2:07 PM Subject: Re: [iText-questions] Embedding external signatures inside PDF files > > On 28.08.2007, at 15:53, Paulo Soares wrote: > >> Each time a signature is applied new ids are created. Signing the >> same PDF >> twice will never have the same hash. > That's not a requirement. The only requirement is to have a single > PDF and a single signature that should be verifiable only with > special software (that knows how to extract the needed information > and knows what to do with the external signature format and how to > verify it). > > The signature in embedded in the PDF file has nothing to do with PDF > signatures - it should not be possible to verify it with adobe > reader for example - only if a special plugin is installed. > > The idea is to have a proprietary signature format encapsulated into > the PDF so that the end user would see a normal PDF with a 'unknown > signature' but with special software it would be possible to turn the > PDF inside out and and get the digital signature payload from inside > the PDF. > > -- > Martin Paljak > http://martin.paljak.pri.ee ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ iText-questions mailing list iText-questions@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/itext-questions Buy the iText book: http://itext.ugent.be/itext-in-action/
