SHOW AND TELL 190: National Security Agency NSA Cryptographic Key Code Challenge Coin (collectible)

SHOW AND TELL [190]: National Security Agency NSA Cryptographic Key Code Challenge Coin (collectible coin).

Wikipedia article on Cryptography : https://en.wikipedia.org/wiki/Cryptography

Wikipedia article on National Security Agency : https://en.wikipedia.org/wiki/National_Security_Agency

Wikipedia chapter on National Security Agency, History, From 1980s to 1990s : https://en.wikipedia.org/wiki/National_Security_Agency#From_1980s_to_1990s

Wikipedia article on Challenge coin : https://en.wikipedia.org/wiki/Challenge_coin