Time stamp and time stamping service

Seal Time Stamping Service 

With the SwissSign Time Stamping Service companies can assure, through the use of timestamps, the legal validity and conformance of their electronic documents.


What are digital time stamps used for?

Timestamps are electronic signed certifications that prove the existence of electronic data and documents at a specific point in time. As an officially recognised provider of certification services (Time Stamp Authority, TSA) SwissSign fulfills the requirements of the Swiss Signature Act ZertES.



Regular business requires documents to be signed with a signature and date. But In the digital business world one can digitally sign documents with the necessary timestamps being delivered via a timestamp service. Timestamps have advantages over the dates associated with a handwritten signature. If a document which has been signed with a digital timestamp is subsequently altered, the timestamp becomes invalid. Thus the “integrity” of an electronic document can be ensured.



  • Accredited and qualified according to Swiss Law 
  • Small budget solution – volume discount with increasing volume, 10 signatures free per day, annual invoice for ordered volume
  • Simple and automated usage based on standard interfaces
  • Proof of time and integrity
  • Only the hash will be signed (a fingerprint of your document) – SwissSign does not see the content of your documents
  • Combined use possible – including signing services, organisation certificates, SuisseID and code signing certificates. In this way you can show evidence of ownership and provide non-repudiation guarantees for your documents.


How does a time stamp service work?

Typically documents have a PDF/A format. Initially a fingerprint of the document will be created – a so-called “hash”. The hash comprises a small set of digits and characters representing the complete document. If the document is ever changed the new hash will be completely different. This hash will be sent to SwissSign. SwissSign signs the hash with its private key. The signed hash is then combined with the original PDF document to produce a signed PDF document. By using the public key of the timestamp service anybody can quickly check whether the timestamp is valid or not.


TSA How does it work


Which software do I need to communicate with the SwissSign Time stamp service?

As SwissSign uses the international standard RFC3161, you can use any standard application which also uses this standard. You simply need to configure your application (for example Adobe Acrobat X Pro) to use the URL http://tsa.swisssign.net in order to address the timestamp service.



SwissSign time stamps can – depending on the requirement of the specific application – be requested and generated in different ways:

  • For the occasional acquisition of up to 10 time stamps per day, where high output, performance and scalability of the service plays a secondary role, you can access the SwissSign timestamping authority via the internet directly from the SwissSign server. As a SwissSign customer, you can use our timestamping authority free of charge.


  • Do you have batch processes which either permanently or frequently need to timestamp many documents or transactions within a short time? Here, SwissSign offers a timestamping authority which, in addition to an annual basic charge, is invoiced based on transactions. 

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  • All binding guidelines for this service are stipulated in the relevant Certificate Policy and Certification Practice Statement (CP/CPS):  Time Stamping Policy


Using Adobe Acrobat X Pro you open the menu "Tools" -> Sign & Certify -> More Sign&Certify -> Security Settings -> Time Stamp and enter the timestamp service as follows


If you would like to use a mass signing application, which timestamps your documents automatically, SwissSign recommends the library and tool set of PDF-Tools in Switzerland which is used by a lot of standard PDF applications.