How can I lock a PDF document after signing it?
Adobe Acrobat has the option to lock the PDF document after signing it. This changes the document permissions so that Acrobat does not offer signing the document again or modifying annotations or forms. This seems like a reasonable action to do after a document has been signed for review by multiple entities and finally for release by someone responsible. iTextSharp can also sign documents, and it can also add further signatures to an already signed document. iTextSharp basically also can set the document's permissions, but somehow I can't get it to set the same permissions as Acrobat X Pro