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  "path": "/2026/04/copiale-cipher-the-mysterious-18th-century-book-that-took-260-years-to-decode.html",
  "publishedAt": "2026-04-27T09:00:42.000Z",
  "site": "https://www.openculture.com",
  "tags": [
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  "textContent": "In the world of cryptography, substitution ciphers are child’s play. Indeed, we may remember literally playing with them as children, writing secret messages to our friends by replacing all the letters with numbers, say, or shifting them one or two places over in alphabetical order. Cracking such codes was a trivial matter even before the […]",
  "title": "Discover the Copiale Cipher: The Mysterious 18th-Century Book That Took 260 Years to Decode"
}