Mobile-ID is an Estonian SIM-based authentication tool to identify yourself and sign online.
The system is based on a special mobile SIM card, which the customer must request from the mobile phone operator. Private keys are stored on the mobile SIM card along with a small application delivering the authentication and signature functions.
Currently it is being issued by Estonian mobile operators to residents only.
Mobile-ID is safe and easy to use for logging in to online services such as Unicount, internet bank, tax office. You can also use mobile-ID to sign your legal documents with Digidoc application.
Unicount recommends mobile-ID to Estonian residents to avoid any software or hardware issues common for smart cards that require a reader with a compatible OS and browser plugin. Compared to Smart-ID it comes at a small monthly charge on your mobile bill.
To register a mobile-ID you need to have Estonian ID-card.
Read more here.