TOTP security tokens and 2-Step Verification
Time-based One-time Password Algorithm (TOTP) is an algorithm that computes a one-time password from a shared secret key and the current time. The most popular implementation of this solution is Google Authenticator.
This application that implements TOTP security tokens . Usually is branded as “ Two-step verification {.mw-redirect}” (or 2-Step Verification). Authenticator provides a six- to eight-digit one-time password which users must provide in addition to their username and password to log into various services or other sites.