DigiDoc4 is a program that can be used to sign digitally with ID-card, mobile-ID, and Smart-ID, check the validity of digital signatures, open and save documents inside the signature container, encrypt and decrypt files and review personal information stored on the ID-card. Digitally signed containers are files with .ddoc, .bdoc or .asice extensions, encrypted/decrypted files are with .cdoc extension.

Web browser components for digital signing can be downloaded from here: https://www.id.ee/en/plugins/