1. A computer-implemented method for authenticating an identity of a target person comprising: determining, from a first system graph comprising publicly available data, connections and connection strengths between one or more hypothetical identities and a plurality of related entities associated with the one or more hypothetical identities; deriving, from a second system graph comprising private data, connections and connection strengths between the target person and one or more real entities associated with the target person without requesting input from the target person; identifying matches between the target person and the one or more real entities associated with the target person and related entities associated with the one or more hypothetical identities based at least in part on the derived connections and connection strengths; and providing an indication of identity authentication of the target person based at least in part on the identified matches.