Code Talker - Cryptographic Properties

Cryptographic Properties

Non-speakers would find it extremely difficult to accurately distinguish unfamiliar sounds used in these languages. Additionally, a speaker who has acquired a language during their childhood sounds distinctly different from a person who acquired the same language in later life, thus reducing the chance of successful impostors sending false messages. Finally, the additional layer of an alphabet cypher was added to prevent interception by native speakers not trained as code talkers, in the event of their capture by the Japanese. A similar system employing Welsh was used by British forces, but not to any great extent during World War II. Welsh was used more recently in the Balkan peace-keeping efforts for non-vital messages.

Navajo was an attractive choice for code use because few people outside the Navajo themselves had ever learned to speak the language. Virtually no books in Navajo had ever been published. Outside of the language itself, the Navajo spoken code was not very complex by cryptographic standards and would likely have been broken if a native speaker and trained cryptographers worked together effectively. The Japanese had an opportunity to attempt this when they captured Joe Kieyoomia in the Philippines in 1942 during the Bataan Death March. Kieyoomia, a Navajo Sergeant in the U.S. Army, but not a code talker, was ordered to interpret the radio messages later in the war. However, since Kieyoomia had not participated in the code training, the messages made no sense to him. When he reported that he could not understand the messages, his captors tortured him. Given the simplicity of the alphabet code involved, it is probable that the code could have been broken easily if Kieyoomia's knowledge of the language had been exploited more effectively by Japanese cryptographers. The Japanese Imperial Army and Navy never cracked the spoken code.