A system and a related method are disclosed for authenticating a user of an electronic system. The system, and related method access (a) data relating to a defined interaction with an input device for a purported authorized user, (b) a probability distribution representation for the defined interaction for an authorized user, and (c) a probability distribution representation for the defined interaction for a wide population, from which it can determine value indicative of whether the purported authorized user is the authorized user. The purported authorized user can be authenticated as the authorized user, if the value satisfies a prescribed threshold.