Here’s a very accessible 1940 article by über-codebreaker William Friedman that I’m sure you’ll like: an appreciation of the cryptography of Jules Verne.

William Friedman – “Jules Verne as Cryptographer” – The Signal Corps Bulletin, April-June 1940 pp.70-107


In the article, Friedman discusses three stories Verne wrote that each hinged on a cryptogram that had to be broken:
* A Journey To The Centre of the Earth (1864)
* The Giant Raft or 800 Leagues On The Amazon (1881)
* Mathias Sandorf (1885).

In two cases it was a transposition cipher, while in the other it was a Vigenère cipher. Of course, it was Friedman himself who invented the whole Index of Coincidence approach for tackling Vigs in a systematic way, and what is nice here is that he reconstructs Verne’s attack on the Vig ciphertext in an easy-to-understand way (short version: Verne got it largely right, but not anywhere near 100%).

Naturally, many will point to Poe’s “The Gold Bug” as the ultimate cipher story: but actually, that used only a simple (monoalphabetic) substitution cipher, so Verne’s work was – cryptographically speaking – much more challenging. I hope you enjoy Friedman’s take on the three ciphers!

Incidentally, the article was recently found, scanned and posted by cryptocollector Brooke Clarke in the book section of his webpage of crypto-related stuff – thanks, Brooke, much appreciated! 🙂

7 thoughts on “The Cryptography of Jules Verne…

  1. bdid1dr on February 21, 2015 at 1:52 am said:

    Thanx, Nick! I thought I had read ‘all’ of Jules Verne’s writings/stories. I’ll be checking out your latest discussion and will be attempting to find the items in our local public library which participates in a tri-counties circulation of just about ‘any book requested at our three local libraries.

    Also, now that you’ve mentioned George Sands………..


  2. bdid1dr on February 21, 2015 at 1:56 am said:

    I seem to be just as careless with quote marks as I am with closing my parentheses — my apologies for the confusion!

  3. hans jahr on February 26, 2015 at 9:10 pm said:

    by Milton Friedman, really?!:)

  4. hans jahr: probably no relation, but you never know. 😉

  5. hans jahr on February 27, 2015 at 5:48 pm said:

    Just to be clear, I refer to:
    Signal Corps Bulletin 108 Jules Verne As A Cryptographer by Milton Friedman
    on Brooke Clarke’s website:

  6. hans jahr: that’s just a typo on Brooke’s part, the article is definitely by William Friedman. 🙂

  7. Hans Jahr on May 29, 2015 at 11:31 am said:

    The NSA has released a huge collection of documents relating to William Friedman. Their statement says: ‘This collection, composed of over 52,000 pages in more than 7,600 documents, including some sound recordings and photographs, has been preserved in the NSA Archives for its historic significance and value. The bulk of the material dates from 1930–1955 and represents Mr. Friedman’s work at the Signals Intelligence Service, the Signal Security Agency , the Armed Forces Security Agency, and NSA’.

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