A method of authenticating the identity of a user to determine access to a system includes providing a plurality of factor-based data instances corresponding to a user, evaluating the factor-based data instances to determine if the user's identity is authenticated, and granting or restricting the user's access to the system if the user's identity is authenticated. More particularly, the method includes providing a modified data instance based on a second data instance, generating a key based on a first data instance, applying the key to the a modified data instance to generate a recovered data instance, interrogating the recovered data instance against the second data instance to generate an authentication value as a result of a correspondence evaluation, and granting or restricting the user's access to the system based at least in part on the validity of the authentication value.