Codebooks examples () ()

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    • Messages from 1690, an unpublished codebook?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)

Introduction

The reign of Louis XIV was very long (from 1643 to 1715). Cryptology in general and French cryptology in particular has evolved considerably during this long period. Spurred on by the Rossignols, the discovery of two part codes (the Great Cipher) really revolutionized cryptology. We have gone from the age of the infancy of encryption to practices that are certainly not indecipherable but very airtight and overall easy to handle.

In this chapter, I have selected some codebooks that illustrate this evolution. We start with a codebook from 1643 worthy of the previous century (16th) and we end with a code of 1701 which would not be ridiculous in the following century (19th). But before this overview, we will present some particularities of French language as it was written in the century of Louis XIV.

References

The cryptology enthusiast who would be particularly interested in code examples should explore the Cryptiania site of the Japanese Tomokiyo. It is the absolute reference.
  • Web portal (Web)
  • French Ciphers during the Reign of Louis XIV (Web)
  • Ciphers Early in the Reign of Louis XIV (Web)
  • French Ciphers at the time of the Fronde (Web)
  • Specimens of French Cipher (1689) Printed in John Wallis' Opera Mathematica (Web)

The writing of French in the 17th century

The French language of the 17th century is very understandable. On the other hand, the writing of this language has several differences with modern French:

  • The use of "y" instead of "i" (especially at the end of a word): j’ay, luy, hyver, …
  • The confusion between "i" and "j", between "u" and "v".
  • The use of "oi" instead of "ai": Les francois et les anglois (the French and the English), je feroi (I will do),
  • Confusion between S and F: In fact, the two letters are not confused, but the "s" can be written in a "short" or "long" way. In the last case, it looks a lot like "f" (it was the same in English).
  • The "w" does not exist (if necessary, we use VV or UV instead)
General Note: The spelling is not "fixed". It will be at the end of the 19th century. For example, the use for the "K" sound of the following symbols: K, C, QU.

References

Examples of codebooks from the time of Louis XIV

  • A codebook from 1643 using special characters for letters.
  • A one part codebook from 1676 but topped with tags that changes meaning of numeric codegroups.
  • A two part codebook from 1676 (the first one?)
  • A one part codebook from 1684 but purely numerical.
  • A code from 1685. The oldest example of using this type of code?
  • A two part codebook from 1688. The oldest example of authentic tables for ciphering and deciphering?
  • Letters from 1690, an unpublished codebook?
  • The codebook from 1691 broken by Bazeries.
  • A two part codebook from 1701.