In the surrounding field of communities and other authorities many forms are available in electronic form, so called eForms. These can be filled out and passed on at the PC. However, as soon as a signature is required a medium break is unavoidable. At the beginning of 2005 a Swiss Federal law (ZertES) will become effective. This law will mainly equalize one's own hand signature with the digital signature. Thus the legal conditions are created to be able to process eForms medium break-free. As technical facility the employment of a Public Key Infrastructure (PKI) as well as the portable document format (PDF) technology is necessarily. The PKI authenticates the connection between a person and a certificate. The PDF technology of Adobe is a wide spread standard for the use of eForms, which supports the securely attachment of digital signatures with an eForm.

In this work we show, how this should function. A document or eForm is produced and marked as original by a first signature. In the passing on, further digital signatures are attached. Each receiver of the document can verify the digital signatures linked to it.

The keys and appropriate certificates used for signing are created by the Certificate Authority (CA) of the PKI which also offers a certificate validating service over the network. In our demonstration we show the complete process chain and interaction with a private Certificate Authority.

It appears that the Adobe Reader must be extended with a suitable Plug-in to be able to create and verify signatures in an easy way. Furthermore an original eForm must be certified with a first signature in an automated way so that the users of the eForm can rely on the authentication and integrity of the eForm.