Digital Signature PDF Documents with JSignPdf

JSignPdf is a Java application which adds digital signatures to PDF documents. It can be used as a standalone application or as an Add-On in OpenOffice.org. JSignPdf is open-source software and can be freely used in both private and business sectors.
The main features are,
* several different keystore types (as provided by Java)
* adding digital signatures to PDFs
* setting certification level
* PDF encryption and setting rights
* adding signature icon to PDF (visible signature)
* comprehensive Swing GUI
* support for batch processing (controlled by command line arguments, without GUI)
for details, please visit here.