A system and method for authenticating a candidate user accessing a host computing device as an authentic user is provided. The host computing device is in communication with an authenticating computing device. The method includes receiving, by the authenticating computing device, a request to authenticate the candidate user as an authentic user. The authentication request includes a user identifier. The method also includes retrieving, by the authenticating computing device, transaction data including payment transactions performed by the authentic user based on the user identifier. The method also includes generating, by the authenticating computing device, a challenge question and a correct answer based on the transaction data associated with the authentic user, and transmitting the challenge question for display on a candidate user computing device used by the candidate user.