Passwords are essential for security and privacy, but they are often not enough. They can be stolen, guessed, or hacked. You might not even know who else has your password and is accessing your account. Two-factor authentication adds a second layer of security to your account to make sure that it stays safe, even if someone else knows your password, by using your phone or other device to verify your identity. You will be alerted right away (on your phone - mobile or landline - or tablet) if someone tries to log in using your password. This prevents anyone but you from accessing your accounts.