Hello,
This has been something thought to be impossible for SA:MP but as of today, I have had multiple successful integration tests working to support Two-factor authentication in-game using Google Authenticator. This is an optional additional layer of security that in addition to a password, requires a security code generated by the Google Authenticator app (available for iOS, Android and Windows phone). We will not be supporting sms, or email based two factor authentication. You can use Google Authenticator or any app which supports TOTP (time-based one-time password).
We will have more information as we progress.