The Trust Service Authority of Slovenia was established as a certification authority in 2001 at the then Government Centre for Informatics of the Republic of Slovenia (CVI). Following a reorganization in 2004, the Government Centre for Informatics of the Republic of Slovenia was transferred under the authority of the Ministry of Public Administration of the Republic of Slovenia with all its competencies, and in 2023, after another government reorganization, it was transferred under the authority of the Ministry of Digital Transformation.

The Trust Service Authority of Slovenia manages the root certification authority SI-TRUST Root; the qualified digital certificate authority SIGEN-CA; the qualified digital certificate authority SIGOV-CA; the qualified digital certificate authority SI-PASS-CA; the digital certificate authorities on the electronic identity card SI-TRUST eID Signature, SI-TRUST eID High Level, and SI-TRUST eID Low Level; as well as the qualified time-stamping authority SI-TSA. It is also the administrator of the SI-PASS online authentication and e-signature service and issues the mobile identity smsPASS, i.e. a one-time password that enables users to create electronic signatures on documents and to log in to e-services that support smsPASS.

Within the Trust Service Authority of Slovenia, the qualified digital certificate authorities and the time-stamping authority were initially established. Today, this framework also includes a digital certificate authority for biometric travel documents, a certificate authority for the purposes of fiscal verification of invoices, a digital certificate authority for online authentication and e-signatures, and digital certificate authorities for authentication and e-signatures on the electronic identity card.