A method for securely authenticating a user of a consumer device at an access device comprising the following steps. First, a dynamic data element and a first set of transactional information is sent to the consumer device from the access device. Next, the consumer device creates an authentication code as a function of at least the dynamic data element, a subset of the first set of transactional information, and a password. The authentication code, along with other data, is then sent from the consumer device back to the access device. The access device then uses the authentication code to send an authentication request message to the service provider of the user. The service provider then attempts to authenticate the user by recreating the authentication code and comparing the recreated authentication code with the authentication code received from the access device.