Two-factor authentication adds an additional layer of security by adding a second step to your login. It takes something you know (ie. your password) and adds a second factor, typically something you have (such as your phone.) Since both are required to log in, even if an attacker has your password they can't access your account.
Passwords are increasingly easy to compromise. They can often be guessed or leaked, they usually don't change very often, and despite advice otherwise, many of us have favorite passwords that we use for more than one thing. So Two-factor authentication gives you additional security because your password alone no longer allows access to your account.
How to enable Two-Factor Authentication at GreenCloudVPS:
I. Log in to your account here: https://greencloudvps.com/clientarea.php
II. Navigate to the Security Settings: https://greencloudvps.com/clientarea.php?action=security
III. Click on "Click here to enable":
IV. Use Google Authenticator (must be installed on your Mobile phone before - it's available on iOS, Android and Windows Phones) to scan the QR then obtain the code:
V. Put in the code then click on "Confirm":
VI. It's done now! Remember to take note of your backup code in case your Mobile phone is not available: