PDF Electronic Signature

  1. Signature representation
  2. Technology
  3. Availability
  4. Contact and further information

By using electronic signatures a high level of security and data protection can be maintained. Thanks to the electronic signature, the authenticity of documents can be guaranteed. Electronically signed documents cannot subsequently be manipulated without leaving visible traces and makes possible to identify and authenticate persons communicating electronically.

PDF-AS follows a novel approach of embedding electronic signatures into a PDF document. A conventional XML digital signature (XMLDSig) is created and attached as a visual signature block to the document. By signing the raw text of a PDF document, the electronic signature can be reconstructed even from paper printouts. Alternatively, the binary PDF data stream can be signed which allows for signing arbitrary content including images, but the reconstruction from printouts is lost.

Electronic signatures that can be reconstructed from printouts are used in Austrian E-government. The evidential value of an official notification is maintained, if the citizen prints the electronic document for archiving purposes.

Signature representation

There is no mandatory regulation for the exact structure of a signature. However, it is recommended to use a uniform appearance for the signature. The PDF-AS application uses following parts for the visual:

  • Signature value
  • Name and role of the signer
  • Date and time of the signature
  • Certificate service provider
  • Certificate serial number
  • Validity hint


The basic PDF-AS application is available as command line tool or as web application. An installation of the PDF-AS web application is available under https://www.buergerkarte.at/pdf-as/. Verification of PDF-AS signature may be performed with the Signature Verification Services available under https://www.signature-verification.gv.at.

The PDF-AS application supports the interfaces as provided by the Austrian citizen card and interfaces provided by MOA-SS for creation of electronic and qualified electronic signatures. For the purpose of signature verification PDF-AS employs the signature verification module MOA-SP.


The basic PDF-AS signature technology is provided in form of a Java™ library, which has been developed in the context of the open source project PDF-AS initiated by Austrian Federal Chancellery and E-Government Innovation Centre (EGIZ) established at the Graz University of Technology. The project is hosted at the Austrian E-government open source platform EGovLabs and is available under the Apache Software License 2.0. The project also provides the PDF-AS web service.

Additionally, a number of other PDF-AS software tools

  • EGIZ Acrobat Plugin (enables to graphical placement of the signature block using drag & drop when using Adobe™ Acrobat)
  • EGIZ tool for creating visual embedded in signatures in PDF documents
  • EGIZ Word Plugin for MS Office™ 2007 for saving signed PDF-Documents
  • PDF-AS-Plugin for OpenOffice.org 2.x and 3.x for saving signed PDF documents

E-Government Innovation Centre (EGIZ) and Secure Information Technologies (A-SIT Austria), respectively provide these tools. For details on the licensing conditions of these tools please see licensing information provided with the projects.

Contact and further information

Further information on the PDF-AS technology is available through the project web site and the PDF-AS information web provided at the citizen card info site. Please contact post@egiz.gv.at for any questions regarding the PDF-AS project.