Martin Gardner

Codes, Ciphers and Secret Writing

“A fascinating, challenging book.” — A. L. A. Booklist. Experiment with cryptography — the science of secret writing. Cipher and decipher codes: transposition and polyalphabetical ciphers, famous codes, typewriter and telephone codes, codes that use playing cards, knots, and swizzle sticks…even invisible writing and sending messages through outer space. Hours of intrigue and challenge. 45 diagrams.
181 printed pages
Original publication


    Dannishared an impression2 years ago
    👍Worth reading

    Fascinating 🤩 Special thanks for all the illustrated cipher examples .


    Dannihas quoted2 years ago
    Not long ago someone asked the famous Chinese physicist Chen Ning Yang what we should do if we ever received an unmistakable radio message from outer space. His reply was:
    “Don’t answer.”
    Dannihas quoted2 years ago
    In the picture, the wheels have been set so that the horizontal line of letters, above the cross-bar, reads: “Have just reached eastern edg.” These are the first 25 letters of a message. The encoder copies down any other horizontal line of letters. The decoder sets the wheels to align the cipher text, then he looks around the cylinder for a line which makes sense. All the other lines, Jefferson wrote, “will be jumbled and have no meaning, so that he cannot mistake the true one intended.”
    Dannihas quoted2 years ago
    Porta’s Digraphic Cipher
    A digraphic cipher is one in which pairs of letters, instead of individual letters, provide the basis of the cipher text. In the Porta Cipher, a single symbol is substituted for every pair of letters in the message. The method was invented by Giovanni Battista Porta, an Italian writer, scientist and magician. At the age of 28 he published (in 1563) a delightful book on codes, which included this one. It is the first known digraphic cipher.

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