olemus
kahe sõltumatu identsustõendiga autentimine,
multiautentimise lihtsaim vorm
= authentication with two independent identity tokens, the simplest form of multi-authentication

ülevaateid
https://www.security.org/digital-safety/authentication-guide-how-to/
https://www.varonis.com/blog/two-factor-authentication
https://en.wikipedia.org/wiki/Multi-factor_authentication
https://www.hhs.gov/sites/default/files/two-factor-authorization.pdf
https://res.mdpi.com/cryptography/cryptography-02-00001/article_deploy/cryptography-02-00001-v2.pdf
https://www.usenix.org/system/files/soups2019-reese.pdf

turvalisus
https://www.knowbe4.com/hubfs/KB4-11WaystoDefeat2FA-RogerGrimes.pdf