A behavioral characteristics authentication system and method (“BCA system”) that facilitates authentication of the identity of a user, registrant, or applicant of a website, application, or other accessible computer resource using a verification process that incorporates behavioral characteristics. In operation, the BCA system compares a single user's behavior with their previous behavior, a user's behavior with behavior generally attributed to non-fraudulent behavior, or a user's behavior with behavior generally attributed to fraudulent behavior. The population of other users that a user's behavior is compared with may be selected to have similar demographic or other characteristics as the user. By analyzing various behavioral characteristics associated with legitimate or fraudulent multi-factor authentication attempts, the BCA system adds another layer of security to online transactions.