How to digitally sign PDF files with XFA forms using iText

问题

iText release notes mention that signing of PDFs with XFA forms is supported from iText versions 5.4.2 and 5.4.3:

http://itextpdf.com/history/?branch=54&node=542

http://itextpdf.com/history/?branch=54&node=543

Is there a documentation somewhere how to do the signing in Java?

I am specifically interested in signing PDFs with XFA where there is a prepared field for signature.

回答1:

This is a small example showing how to sign using XmlDSig:

PdfReader reader =new  PdfReader(src);
FileOutputStream os =new  FileOutputStream(dest);
PdfStamper stamper = PdfStamper.createXmlSignature(reader, os);
XmlSignatureAppearance appearance = stamper.getXmlSignatureAppearance();
appearance.setXmlLocator(new  XfaXmlLocator(stamper));
appearance.setXpathConstructor(new XfaXpathConstructor(XfaXpathConstructor.XdpPackage.Datasets));
ExternalSignature signature =new  PrivateKeySignature(pk, digestAlgorithm,"BC");
//use signXmlDSig or signXades
MakeXmlSignature.signXmlDSig(appearance, signature, chain);

You can also sign using XAdES, but then you won't be able to validate the signature in Adobe software because I don't think Adobe already supports XAdES (please correct me if I'm wrong).

来源：https://stackoverflow.com/questions/19030113/how-to-digitally-sign-pdf-files-with-xfa-forms-using-itext