TSA, or time stamp service, is a solution that proves that certain data existed at a given point in time.
Under DigiDoc4 Client settings it is possible to set access to the Time-Stamping service.
To set a Time-Stamping service URL:
1. Launch the DigiDoc4 Client application.
2. Open at the top right "Settings".
3. Under Settings, select "SIGNING SERVICES".
4. Set the TSA URL in the "Access to Time-Stamping service" box and select the "Use manually defined access" option.
5. If you are using the HTTPS TSA service, you must also add an SSL certificate for your TSA service. The certificate can be added using the "ADD CERTIFICATE" button."
Authorities can also set the Time-Stamping service URL via registry. More information about registry parameters can be found here.