Do I have to sign up for Two-Factor Authentication or is it automatic? If you want the added security of Two-Factor Authentication, you have to opt in. Although we highly recommend that you opt in to this added layer of protection for your accounts, it is not required that you do so. How to opt in to Alliant Two-Factor Authentication: Log in to Alliant Online Banking and select My Profile & Settings. Select Access & Security, then Protect Your Account with Two-Factor Authentication. Type your U.S.-based mobile phone number into the Mobile Number field if the number displayed on the page is incorrect (or if the Mobile Number field is blank because you have no mobile phone number on file with Alliant), check the box that indicates your agreement to the terms of service and click the Continue button.