TOTP Authenticator Apps To generate a 6-digit code for two-factor login verification, you’ll need an app. Below is a list of apps you can use for this purpose—but if none of these suit you, there are plenty of other compatible options out there. Info TOTP is an abbreviation for Time-Based One-Time Password FreeOTP This app was developed by Red Hat and supports TOTP and HOTP. It can be protected with your phone’s biometric scanner or a pin code....