Two-factor authentication is getting a stronger padlock to further secure your Google account. Currently you can further secure your account by getting a code via text message (or phone call), or with a code from the Google Authenticator app. A new Google prompt adds a third option. You'll see a simple prompt to approve the new sign-in request. Whenever you go to sign in somewhere new with your Google account, you'll see a simple pop-up notice to approve or deny the request.