Cryptex is a Néologisme used by Dan Brown in her novel Da Vinci Code to indicate a kind of extremely portable trunk designed for hiding secret messages.

This term is resulting from the combination of the words Cryptologie and Codex. This object, whose paternity is allotted to Léonard de Vinci, uses “cryptology to protect from the information themselves noted on a or scroll of parchment codex ” (CH. 47 of the French translation by Daniel Roche).

The author affirms that “the majority of the inventions of Léonard had been studied never nor even baptized”, from where need for resorting to neologisms to indicate some of the lucky finds of the Italian genius.

Design

The cryptex of the novel of Dan Brown is described as being a “polished marble cylinder” resulting from “the assembly of five juxtaposed stone discs, of approximately three centimetres of broad, maintained one against the other by a copper reinforcement”, such a “Kaléidoscope with five axes”. The ends of this cylinder “are closed by a sealed stone capsule”, so that one cannot see inside. On each marble disc are the present “twenty-six letters of the alphabet”.

This cryptex “functions roughly speaking like a theft protection device of bicycle”: “it is a word of five letters which will actuate the lock and will make it possible to open the cylinder”. Inside the cryptex, “the hollow compartment is designed to contain a paper roller where was noted secret information”.

This paper, supposed being a very fine papyrus, is rolled up around a vinegar tube out of fine glass, which prevents any opening of force of the cyptex to obtain the message: that would break the tube of glass and would spread the vinegar on the parchment which would consequently become illegible.

Can such a process function?

It is not certain that the vinegar can dissolve the papyrus indeed: if it is probable that such a liquid would damage the papyrus, this one would not be necessarily instantaneously illegible.

However, it would undoubtedly be possible to create a paper specifically designed to disaggregate in contact with the vinegar. For example, it would be necessary to combine paper fibers with a solution of Bicarbonate: this element reacts chemically in contact with the vinegar, it forms bubbles of Carbon dioxide which would separate fibers from paper.

However, even if it is possible to consider an efficient design of the mechanism of self-destruction, the degree of safety brought by the cryptex would be tiny with our knowledge of today: the current processes scannographic (such as the Ultrasound S or the X-rays) would make it possible to reveal the internal mechanism of the object and to find the combination adequate.

In addition, a solution of opening of the apparatus was omitted by the author: the vinegar easily which can be frozen, it would be enough to place the object at the freezer for then opening it of force without being likely to dissolve the papyrus.

See too

• History of cryptology