Michael,
Thanx for so quick reply. You made me confused about those attributes,
you're absolutely right.
Let me ask You one more question. Is there ANY chance to make my
transformation? Maybe setting some ranges for byterange hashing for PDF,
excluding additional dataobjects? Anything? Modification of
signing-process-flow is unfortunately impossible :-(
TK.
2009/8/27 mkl <[email protected]>
>
> Hello Thomasz,
>
> so you have a regular XaDES signature for the original PDF file and try to
> convert it into a PDF with an integrated signature?
>
> I'm afraid this is impossible. In a PDF with an integrated signature, the
> hash is not merely calculated for the original PDF revision you had to sign
> but also for the additional PDF objects required to embed the signature.
>
>
> Tomasz Korolczuk wrote:
> > try {
> > sap.preClose(exc);
> > } catch (IOException e) {
> > e.printStackTrace();
> > } catch (DocumentException e) {
> > e.printStackTrace();
> > }
> >
> > byte[] hash = null;
> > hash = Base64.decodeBase64(xml.getDocumentDigest().getBytes());
>
> If you had not removed the original code used to calculate the hash digest,
> you could have compared it to the digest you take from the XML; you would
> have seen that they differ.
>
> If you could change the process in a way that the XaDES signature is not
> created for the original PDF but for the range stream returned by
> sap.getRangeStream() after sap.preClose(exc), your chances get better to
> produce something usable.
>
> Unfortunately in your code you later build a new signedAttributes object.
> Why do you expect you do it identically to how it was done by the code that
> created the XaDES signature?
>
> I'm afraid it's back to cryptography 101 and the whiteboard...
>
> BTW,
>
>
> Tomasz Korolczuk wrote:
> > stamper = PdfStamperOSP.createSignature(reader, os, '\0');
>
> it generally a good idea to use the createSignature overload with the
> append
> parameter and set it to true, as otherwise prior signatures are rendered
> broken.
>
> Regards, Michael.
> --
> View this message in context:
> http://www.nabble.com/Problem-with-transforming-PDF-from-XADES-signed-XML-file-info-%22normal%22-signed-PDF-tp25167508p25167534.html
> Sent from the iText - General mailing list archive at Nabble.com.
>
>
>
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--
--
Tomasz Korolczuk
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