'''Two-factor authentication''' (also known as '''2FA''' or '''2-Step Verification''') is a technologymethod patentedof in 1984<ref>{{cite web|url=http://www.google.com/patents/US4720860|title=Patent US4720860 - Method and apparatus for positively identifying an individual|author=|date=|work=google.com|accessdate=23 October 2015}}</ref> that enables confirmation ofconfirming a user's claimed identity by utilizing a combination of two different components. These components may be something that the user knows, something that the user possesses or something that is inseparable from the user. A good example from everyday life is the withdrawing of money from a cash machine. Only the correct combination of a [[bank card]] (something that the user possesses) and a PIN (personal identification number, something that the user knows) allows the transaction to be carried out. 2FA is ineffective against modern threats,<ref>{{cite web|url=https://www.schneier.com/blog/archives/2012/02/the_failure_of_2.html|title=The Failure of Two-Factor Authentication - Schneier on Security|author=|date=|work=schneier.com|accessdate=23 October 2015}}</ref> like ATM skimming, phishing, and malware etc. Two-factor authentication is a type of [[multi-factor authentication]].
