Navajo Code Talkers
Navajo Code Talkers were employed by the United States government during World War II to communicate information during war in the Pacific. The Japanese government never broke their code.
Further Reading:
NAVAJO NATION – INVENTORS OF THE UNBREAKABLE CODE. https://www.intel.gov/publics-daily-b...
9 Things Every American Should Know About the Navajo Code Talkers. https://www.military.com/history/9-th...