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. You can use this application when you want to restrict access to certain PDF files.

Features:
1. visible signatures - image and/or description located visualy in a PDF file (page and position can be specified)
2. several different keystore types (as provided by Java)
3. timestamps from authority in signature (TSA)
4. certificate validation through OCSP
5. setting certification level
6. PDF encryption and setting rights
7. comprehensive Swing GUI
8. support for batch processing (controlled by command line arguments, without GUI)

Requirements:
* Java Runtime Environment (included in the installer)

The license of this software is Free, you can free download and free use this pdf software.