olemus
autentimine mitme eri tüüpi identsustõendiga,
näiteks kiipkaardi, parooli ja biomeetrikuga

ISO/IEC 19790, 19092, 27040 jt:
autentimine vähemalt kahe sõltumatu autentimisteguriga

näiteid
- kaksikautentimine
- nelikautentimine

ülevaateid
https://www.youtube.com/watch?v=jxoVC0hUbCQ

https://jon.oberheide.org/files/mmc10-mfauth-jonoberheide.pdf

https://en.wikipedia.org/wiki/Multi-factor_authentication

https://www.rand.org/content/dam/rand/pubs/technical_reports/2011/RAND_TR937.pdf

https://res.mdpi.com/cryptography/cryptography-02-00001/article_deploy/cryptography-02-00001-v2.pdf?filename=&attachment=1

http://ijcsn.org/IJCSN-2014/3-5/Ameliorate-Security-by-Fifth-Factor-Authentication.pdf

https://nccoe.nist.gov/sites/default/files/library/project-descriptions/cr-mfa-project-description-draft.pdf

https://en.wikipedia.org/wiki/Strong_authentication

turvalisus
https://www.wired.com/story/multifactor-authentication-prompt-bombing-on-the-rise/