"Encrypted" is too strong a word. But the code talkers needed a way to represent English that didn't have a natural Navajo equivalent.
So they developed a vocabulary of 411 Navajo words to stand for common military terms. E.g., BESH-LO, which is Navajo for "iron fish", meant "submarine".
The vocabulary included a phonetic alphabet to represent the 26 English letters. E.g., the three Navajo words MOASI, TLA-GIN, and BA-GOSHI all represent English words beginning with C (cat, coal, cow). So, they could spell out arbitrary English words not in their vocabulary.
It was secure against an enemy that lacked Navajos and probably didn't even know what language was being spoken or if they were intercepting some weird form of audio scrambling. But, if the Japanese had been able to translate the messages to English, the code would probably not have survived cryptanalysis for long.
https://www.cia.gov/stories/story/navajo-code-talkers-and-th...
So they developed a vocabulary of 411 Navajo words to stand for common military terms. E.g., BESH-LO, which is Navajo for "iron fish", meant "submarine".
The vocabulary included a phonetic alphabet to represent the 26 English letters. E.g., the three Navajo words MOASI, TLA-GIN, and BA-GOSHI all represent English words beginning with C (cat, coal, cow). So, they could spell out arbitrary English words not in their vocabulary.
It was secure against an enemy that lacked Navajos and probably didn't even know what language was being spoken or if they were intercepting some weird form of audio scrambling. But, if the Japanese had been able to translate the messages to English, the code would probably not have survived cryptanalysis for long.
https://www.cia.gov/stories/story/navajo-code-talkers-and-th...