What is two-factor authentication (2FA)?
Two-factor authentication (2FA) protects an account by requiring two proofs: your password, then a temporary code generated on your phone. A stolen password is no longer enough to get in. A dedicated app is safer than codes received by SMS, which can be intercepted through your phone number. The topic continues in chapter 11 of my book, Vivre sans Google.
Information verified on July 13, 2026
A second lock on the door of your accounts. Your password opens the first one; two-factor authentication adds another, which asks for a temporary code that only you can provide, most often from your phone. Without that code, nobody gets in, even with the right password.
Why bother with it? Because passwords leak. They get guessed, sold after a breach, or typed one tired day into a fake site. With 2FA on, a stolen password is no longer enough: the thief stays stuck at the second lock, and your account holds.
That leaves the right kind of code to choose. SMS is better than nothing, but it is fragile: a fraudster can get your number transferred and receive your codes in your place. A dedicated app, which generates codes directly on your phone without going through the mobile network, removes that weak spot.
Where it plays out: chapter 11 of the book covers securing your accounts during the migration, the Authenticators (2FA) category compares serious apps, and the de-Google Android guide shows where this setting comes up on your phone.
This topic is chapter 11 of my book
It answers these questions, among others:
- which accounts do you start with, and at what pace, to stay the course?
- are physical keys worth it, and have your passwords already leaked?
- and why is this the one project everyone wrongly puts off?
Forthcoming 22/10/2026 from Éditions Eyrolles
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