Wikipedia
TUPAS is a strong digital authentication method created by the Federation of Finnish Financial Services. TUPAS identification is a de facto standard for digital identification in Finland. It is used by all major Finnish banks including Aktia, Osuuspankki, Nordea, Danske Bank (formerly Sampo), and S-Pankki (formerly Tapiola). Furthermore, TUPAS is used also by Finnish government to log in to Kansaneläkelaitos and Finnish Tax Administration site vero.fi.
TUPAS is based on the Finnish law on strong electronic identification and digital signatures. The law requires a strong identification methods to include at least two of the three following identification methods.
a) Password or other similar that one knows,
b) Chipcard or other similar that one possesses, or
c) Fingerprint or other similar that is unique to the person.
Commonly the identification is done using a password and a list of single-use passcodes or a passcode device.