Messages from 1690, an unpublished codebook? () ()

My Web page about Cryptology

The Louis XIV's codebooks

  • Introduction (introduction)
  • The invention of the great chipher (invention)
  • Analyse of Louis XIV's codebooks (analyse)
  • Cryptanalyse (break)
  • Codebooks examples (examples)
    • A codebook from 1643
    • A one part codebook from 1676
    • A two part codebook from 1676 (the first one?)
    • A one part codebook from 1684
    • Messages encoded by a two part codebook from 1685
    • A two part codebook from 1688
    • Messages from 1690, an unpublished codebook?
    • The codebook from 1691 broken by Bazeries
    • A codebook from 1701
  • The Man in the Iron Mask (mask)

Encrypted letters from 1690

The memoirs of Marshal Catinat are full of examples of codes from the time of Louis XIV. Here is a new example.

Indeed, in these memoirs we find several partly encrypted letters exchanged between Louvois and Marshal Catinat during the year 1690. The translation of the letters being provided, I thought I could easily reconstruct the code. In addition, two long repetitions appeared, one of which turned out to be "the enemies". I was ready to continue my reconstruction work when I had the idea (I could have had it earlier) to test if the code of 1691 reconstructed by Bazeries could apply. I had a big surprise: the letters of 1690 could be deciphered by the code of 1691. So I had found a sample code that had been used for over a year.

Here are the letters:

I deciphered each of these letters. The decryption of the one addressed to Mr d'Herleville produced no comprehensible text. The conclusion is simple: Louvois used a different code from the one he used with Catinat to communicate with Herleville.

The code reconstructed by Bazeries is almost complete, but it still lacks a few codegroups: 19, 71, 161, 228, 250, 253, 291, 319, 334, 552. Unfortunately none of these groups appear in the letters of 1690. Likewise the code 330 which Bazeries has (in my opinion falsely) interpreted as "mask" is not there.

An example of decryption

Here is an example of a decryption of the September 10 letter: 

  9: 480. 151. 74. 544. 26.  125. 230. 449.    119. 318.
     .    .    don t    vous ne   m    expliqu e    z
 10: 338.  337. 149. 389. 152. 415. 252. 289. 453. 394.
     point la   si   tu   a    tion c    est  a    dire
 11: 205. 490. 289. 187. 200. 2.       390. 198. 503. 569.
     t    c    est  u(v) n    quartier ou   vous pour ri
 12: 522. 578. 227.  526. 106.   284. 92. 88. 10. 159.
     e    t    tenir des  troupe s    pe  n   da  nt
 13: 316. 363.   407.   565. 367. 151. 525. 81. 270. 149.
     l    hi(hy) ue(ve) r    .    .    ...

References

  • Mémoires et correspondance du maréchal de Catinat (tome 1) (Google)