To view electronically signed PDF documents, we recommend that you use Adobe Acrobat Reader (freeware).
Outside the Federal Administration or other managed software environments, Adobe Acrobat Reader (freeware) is being used less and less. Other PDF viewers, such as those installed in web browsers and on smartphones and tablets are usually unable to recognise, display, or validate electronic signatures.
Electronically signed Federal Administration documents for addressees outside the Federal Administration therefore always contain a visible representation in the normal content of the document indicating the presence of a signature. The representation can be inserted in two possible forms:
- in the form of a symbol for the type of certificate used (qualified, advanced class B, regulated seal) followed by the name of the signing person/organisation, or
- in the form of a QR code on the top right of the first page indicating whether the document includes electronic signatures or a seal.
Although Adobe Acrobat Reader can at least check the technical validity of electronic signatures, for checking the validity of electronic signatures under Swiss law, we recommend the Validator of the Federal Administration. This validates only Swiss qualified signatures and some advanced signatures of Swiss authorities whose certificates are issued by the Swiss Government PKI. Other signatures, in particular advanced signatures and qualified foreign signatures, can be verified with Adobe Acrobat Reader provided that the root certificates are known to Adobe Acrobat Reader. Root or intermediate certificates that are no longer valid will not be validated correctly.
Technical side note:
Under Edit/Preferences/Trust Manager, Adobe Acrobat Reader lets you choose between the Adobe Approved Trust List (AATL) and the European Union Trusted Lists (EUTL) for validation. If EUTL is selected, all certificates of Swiss providers are validated as not valid. If AATL is selected, the certificates of most Swiss providers are validated as valid even if they are not qualified or regulated certificates. As a consequence, the validating person must display the content of the certificate and also know which root certificates and which intermediate certificates are used by the Swiss providers for qualified certificates or regulated seals. The default setting when installing Adobe Acrobat Reader is that both AATL and EUTL are enabled. This allows Swiss signatures (qualified and advanced signatures and regulated seals), EU signatures and some non-European signatures to be verified and validated if necessary.