Alex KuklinDescription and algorithm
https://en.wikipedia.org/wiki/Time-based_One-Time_Password
Client implementations
- https://github.com/Authenticator-Extension/Authenticator (Chrome, Firefox, Edge)
- https://play.google.com/store/apps/details?id=org.fedorahosted.freeotp (android)
- https://play.google.com/store/apps/details?id=com.google.android.apps.authenticator2 (android)
- https://www.nongnu.org/oath-toolkit/man-oathtool.html
Recovery/emergency codes
Get and store in a secure way