Hi!

Javadoc wrote:
> I am in a situation where I need to create the PDFSignatureAppearance for
> a PDF I am signing twice.

Your problem has been discussed here quite often, e.g. in 

http://www.nabble.com/Pdf-signature-Issues-to23059531.html

or

http://www.nabble.com/Hash-computation-problem-to22801988.html


Javadoc wrote:
> The only thing I can see that would be difference when creating the
> signature twice would be the date name field signDate (signDate = new
> GregorianCalendar(); in constructor).

 You forgot to take the individually created /ID entries in the trailer into
account. Also there is the ModDate in DocInfo and XMP.

 For your requirement you have to change or enhance iText a bit (it's not
too complicated, though). Some hints on how to do that can be found in the
threads pointed to above.

 Your requirement, though, is a bit against the nature of PDF as each time
you start to manipulate some document (e.g. by preparing it for signing),
you generate a completely new unique revision; thus starting twice to sign
conceptionally should create different revisions having different hash
values.

 Maybe, therefore, you should change the architecture of your software
instead of iText.

Regards, Michael.
-- 
View this message in context: 
http://www.nabble.com/Creating-the-same-PDFSignatureAppearance-twice....-tp26070126p26077237.html
Sent from the iText - General mailing list archive at Nabble.com.


------------------------------------------------------------------------------
Come build with us! The BlackBerry(R) Developer Conference in SF, CA
is the only developer event you need to attend this year. Jumpstart your
developing skills, take BlackBerry mobile applications to market and stay 
ahead of the curve. Join us from November 9 - 12, 2009. Register now!
http://p.sf.net/sfu/devconference
_______________________________________________
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
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/

Reply via email to