Ancient Ciphers in History

Cryptography · Axiom Academy

REAL WORLD Ancient Ciphers in History Discover how cryptography shaped empires, wars, and royal fates throughout history It's 1586. Mary, Queen of Scots, sits in an English prison cell. She has been held captive for 19 years by her cousin, Queen Elizabeth I. Her only hope for freedom lies in a secret plot to assassinate Elizabeth and claim the English throne. Mary sends encrypted letters to her conspirators, believing her cipher is unbreakable. But Elizabeth's spymaster, Sir Francis Walsingham, has been reading every word. The decrypted letters will seal Mary's fate—she will be executed for treason in 1587. The Fatal Cipher: Mary used a substitution cipher with 23 symbols replacing letters, plus special symbols for common words and names. She thought it was secure, but Walsingham's codebreaker, Thomas Phelippes, cracked it using frequency analysis —a mathematical technique that exploits patterns in language. This wasn't the first time cryptography changed the course of history, and it wouldn't be the last. Let's explore how ancient civilizations used mathematical principles to protect their secrets—and how understanding these principles could mean the difference between life and death. The Spartan Scytale (5th Century BCE) The ancient Spartans were renowned warriors, but they also understood the importance of secure military communications. They invented one of the earliest known encryption devices: the scytale (pronounced "SKIT-a-lee"). Original Message: ATTACK AT DAWN

This is the written version of the interactive lesson above. See the full Cryptography course.