Strong Authentication is a commonly-used term that is largely without a standardized definition. It is often used synonymously with two-factor authentication or multifactor authentication However, that usage is misleading because some types of very secure authentication rely on a single authentication factor. It requires strong or two-factor authentication. In two-factor authentication, a user provides a token and inputs a password. Additionally, the application should know the way to authenticate the token or password data to allow access to the restricted data.