Many Web sites and apps now offer two-factor authentication (2FA), which requires you to enter a short numeric code—the so-called second factor—in addition to ...

SMS text messages are a weak, dangerous way of providing two-factor authentication codes, as we discussed years ago in “Facebook Shows Why SMS Isn’t Ideal for Two-Factor Authentication” (19 February ...

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Many apps and websites require you to enter a verification code to log in. For some services, you only need to enter your phone number or email address and then use a ...