1. A system, comprising: circuitry for confirming at least one indication of an inferred familial relation associated with at least one user, the familial relation inferred at least partly based on at least one social network interaction; circuitry for incorporating the at least one indication of an inferred familial relation into at least one behavioral fingerprint associated with the at least one user based at least partly on confirming the at least one indication of an inferred familial relation; and circuitry for authenticating an identity of a purported authorized user in association with a purchase transaction using a mobile device associated with the at least one user based at least partly on the incorporated at least one indication of an inferred familial relation of the at least one behavioral fingerprint associated with the at least one user, including at least: circuitry for determining an electronic address for the familial relation based at least partly on the at least one behavioral fingerprint associated with the at least one user; circuitry for transmitting at least one message to the determined electronic address for the familial relation, the transmitted at least one message requesting confirmation that the purchase transaction using the mobile device is likely associated with the at least one user; and circuitry for, responsive to at least one message received from the electronic address for the familial relation, authorizing the purchase transaction if the familial relation provides confirmation via the received at least one message that the purchase transaction using the mobile device is likely associated with the at least one user.