In the business world, it very often comes down to adhering to deadlines and this is no exception for public authorities. Therefore it makes sense and in some cases is required by law, that in addition to the sender's signature, electronic documents must also be given a timestamp.
In order to prove that a deadline has been met, it may be necessary to document electronically when a document arrived or was sent, and at which time the recipient picked it up. The requirements for a qualifying timestamp authority are found in the Austrian Signature Act. A qualified timestamp authority is currently being run by the Federal Office of Meteorology and Surveying.