Communications: Cyphers and Codes

A file of correspondence and memoranda concerning codes and cyphers. The documents include proposals for new cypher systems from members of the public; suggestions that the French and American diplomatic cypher systems are too weak, and are open to enemy decipherment; plans to issue a new cypher system to the Free French forces; discussion of the organisation of the British cypher departments, including the rejection of new cypher machines on the grounds of cost; Dutch pre-war worries about the copious cypher-traffic from the Japanese legation in Batavia; and suggestions that the Japanese are aware that their cyphers have been broken, and are filling them with misinformation and false intelligence.