I've heard that fingerprints must be equal from life to life. Ian stevenson and his successors watched cases for tens years, they could find source materials to check this idea.[i don't know if they've done it or not] If this is true than this is basis for identification. Database can be created, anybody of us can leave his[er] trace there and than future myself comes to identify himself with previouse himself. Information for life, money as inheritage [from myself to future myself] can be left. So called karma than can be examined and research if we could find detailed reports about same person in several of his[er] life.