A virtual talk by Professor Chris Christensen

IKA, ORANGE, and JADE

In addition to hand ciphers and enciphered code, during World War II the Imperial Japanese Navy (IJN) used a cipher machine, designated as JADE by the US Navy, to communicate among their large naval installations.

JADE was the third in a series of such machines that began in the early 1930s with IKA which was followed by ORANGE.

This presentation will describe the history, operation, and evolution of these IJN cipher machines and explore some of the ideas used by the US Navy in their attack on JADE.