Adobe Reader must be configured for the electronic signature. The configuration is provided centrally via an Adobe configuration file and includes the DFN-PKI certificate chain, the DFN-PKI timestamp for a trusted timestamp, and, on Microsoft Windows, integration of the DFN-PKI LDAP directory. The instructions require Adobe Reader to be installed. The necessary steps are similar under other versions of Adobe Reader as well as under Adobe Acrobat.
Note: If you open a signed PDF in the MAC OS preview and click into the document, e.g. on the signature, the original file will be changed by default, making the signature unusable and or invalid. This means that viewing signed PDFs with on-board tools can damage contracts or deeds.
Solution: activate the option "Ask if changes should be kept when closing documents" in the system settings:
Launch Acrobat Pro DC and select Preferences... from Edit.
First, make sure Adobe is familiar with the T-TeleSec Global Class 2 certificate required by TU Dresden.
Under Categories on the left, click the Signatures option. In the Identities and Trusted Certificates section, click the More... button. The Settings for digital IDs and trusted certificates window opens.
Click Trusted certificates in the navigation menu on the left. Make sure that a certificate with the name and issuer T-Telesec Global Root Class 2 is missing in the displayed list. You can download the certificate T-Telesec Global Root Class 2 from this link or directly from the DFN PKI web pages.
Then select the Import button at the top.
Another window will open, go to Browse... and open the downloaded certificate. An entry "T-TelSec GlobalRoot Class 2" is now listed in the Contacts section.
Continue by clicking on Import.
A dialog box "1 issuer certificate(s) imported" appears. Confirm this with OK. The list of trusted certificates now includes an entry "T-TelSec GlobalRoot Class 2" as the name and issuer of the certificate.
Select the certificate and click the Edit trusted certificate button. Now check the Use this certificate as trusted root and Certified documents options. Close the window by clicking OK.
Click the Security from Categories on the left. On the right side of the window, check Load security settings from a server. Enter in the URL field:
https://tu-dresden.de/zih/ressourcen/dateien/dienste/arbeitsumgebung/e_mail/dateien/tu_dresden_adobe_security
In the field Settings must be signed by please select the option Allow any certificate. Then click the Update now button.
In the following windows click Yes or OK.
Finally, select your certificate as "Use for signing". (If your certificate is not installed yet, install it with a double click your Mac).
You will get an information that the settings have been updated successfully. Please click OK and close the Preferences window with the OK button .
You have successfully configured Adobe.