Two-Factor Authentication

Technical Practical technology self systems

Etymology

From "factor" in the sense of a distinct element of proof, plus "authentication," from Greek "authentikos," genuine. The design combines factors of different types: something you know (a password), something you have (a phone or key), or something you are (a fingerprint). The strength comes from the categories being different, so one compromise doesn’t hand over the rest.

noun phrase · /TOO-FAK-tur aw-then-ti-KAY-shun/
Requiring two different kinds of proof to log in, so a stolen password alone isn’t enough.
What it names
The single most effective everyday defense against account takeover — the layer that stops a leaked password from becoming a break-in.
Example
Even after her password leaked, two-factor authentication blocked the intruder at the code prompt.
Related idea
Two-factor is stronger than a password alone precisely because the second factor is a different kind of thing — two passwords would still be one category, and one phishing page could capture both.