On Sat, 2002-07-20 at 16:55, Miguel A Paraz wrote:
> Hi,
> I've been reading the code and I hope to get some tips.
> On Wed, Jul 17, 2002 at 02:58:13PM +0200, Keiron Liddle wrote:
> > If I understand it properly you would need to add an Encrypt pdf object
> > that is referenced in the documents trailer dictionary.
> That is, write out the signature with PDFDocument.outputTrailer?
> Or, add it to trailerObjects using addTrailerObject?

Add a new object to the pdf file that is referenced in the trailer
dictionary using the pdf object reference.

> > The you would need to encrypt all pdf streams using the appropriate
> > algorithm. If JCE can handle this then it would be used to encrypt the 
> > stream.
> Thus I will subclass PDFFilter.
> >From my reading of the code, the scope of the PDFFilter is only inside
> the PDFStream, and the document is composed of multiple PDFStreams.
> If I am correct, then the signing process has to be closer to the output 
> level. For instance, using a FilterOutputStream to peek at the data being 
> written out at the PDFRenderer level.  Or, I could use a single
> java.security.Signature instance for all the PDFFilter subclass instances.
> If I am wrong, and I can use a PDFFilter subclass, how can I extract my
> java.security.Signature instance from the PDFFilter, to write it out
> (java.security.Signature.sign())?  The filters in PDFStream are not 
> referenced by name.

As I misunderstood the original question it appears there is a slight
difference to what needs to be done.
What exactly does it need to do to sign a pdf file. Does it need to read
all data in all streams and then create a single signature number. If so
then it sounds like there needs to be some adjustment to how the filters
are created and used in order to accomodate what you want.

> > - organise the configuration for password etc.
> If a PDFFilter subclass is to be used, how can this have access to the 
> configuration file? 

I don't know. What do you think it should do?

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