Hello,
I know that, it's possible to sign existing PDF files by adding new objects (such as Signature dictionary) and incrementally modifiying Catalog, Pages objects etc. accordingly. But what about the programs producing the PDF file? I mean, should they also implement signing by adding some objects after the trailer and using incremantal updating or should they directly produce signing-related objects inside the document and not use incremental updates? Is there any difference? Is the implemention using incremental updates easier?