This post originally appeared on blog.securityevaluators.com
Two-Factor Authentication (2FA, also known as Multi-Factor Authentication, or MFA) is all the rage these days, and for good reason. Accounts secured by 2FA are much, much harder to compromise than accounts using only a single factor — so much more so that you can — sometimes — get away with an easier to type and remember (and therefore weaker) password when using it. The most common ways of implementing the second factor are SMS and TOTP (Time-Based One Time Password). When SMS is used, the site sends you a short numerical code via SMS after you enter your password, and you type the code into the site to finish proving your identity. SMS is inconvenient (you have to have your phone on you), and more importantly, SMS is insecure and not recommended, so many sites are moving to TOTP codes instead, which involves using an app to generate codes yourself instead of the site sending them to you. There are a variety of apps that you can use to generate these codes, and some password managers do it too — but you have to be careful: your choice of app could weaken the security benefits provided by TOTP.
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