[Cryptography] National Navajo Code Talkers Day

[Dave Horsfall]

Today is National Navajo Code Talkers Day; it was used for crypto comms in 
WW-2, as only a few tribes could speak it.  There were no words for modern 
objects, so "shark" was used for "destroyer" etc, thereby obfuscating it 
further, and clipped phrases meant that fluent but untrained speakers 
would not understand it.

We'll leave aside for the moment the question of how the Navajo tribes, 
being basically inland, could know about sharks...  My summaries are only 
as good as my sources.

-- Dave