Multifactor Authentication $($MFA$)$

Many enterprise end users use a single password to gain access to all computing resources. This is known as single sign$-$on $($SSO$).$ This simplifies the authentication process of an end user but also makes it easier for an attacker to compromise the process. To mitigate the risk, multifactor authentication $($MFA$)$ uses a regular password and a time$-$based one$-$time password $($OTP$).$In this module, the one$-$time password is generated by using the Google Authenticator app available to Android and iOS devices.

How can Common$-$auth Configuration File be difficult?