““between 321 and 300 B.C., recommended that ambassadors use cryptanalysis to obtain intelligence: “If there is no possibility of carrying on any such conversation (conversation with the people regarding their loyalty), he [the envoy] may try to gather such information by observing the talk of beggars, intoxicated and insane persons, or of persons babbling in sleep, or by observing the signs made in places of pilgrimage and temples, or by deciphering paintings or secret writings.””