If you want full security for your Google Accounts than you must enable 2-Step Verification which adds an extra layer of protection to your account. Once enabled, you’re asked to verify your account either by using phone verification or by using a Google Security key, a device which you can attach to your key ring just like any regular key but it is for your account.
To get it working, you must first enable 2-Step Validation by visiting the following link:
Once enabled you will need to use the Google Security Key to be inserted every time you log in to your Google Account.
Now what is the Google Security Key and how it works?
Basically it is a USB second factor device that works after it does verify that the login site is indeed Google’s website and not some phishing site. To use it simple insert the device into a USB port and tap it when prompt at Chrome during login.
If you would like to stay logged into the particular device than you simply select the check-box “Don’t ask for my Security key again on this computer” and you will no longer be asked to enter the Security Key any more.
Google Security Key and Chrome are incorporated with the open Universal 2nd Factor (U2F) protocol from the FIDO Alliance which provides the standard for this service.
Google Security Key (FIDO U2F) devices can be bought from here and also here.