Locked state of the cryptex

The cryptex, a marble cylinder designed by Leonardo da Vinci and built by Jacques Saunière, remains locked throughout most of the novel, its five-letter password unknown to the protagonists. Its sealed state drives the central quest, as the characters must decipher a series of clues—a numeric code, an anagram, a poem, and a riddle about a knight's tomb—to unlock it and access the map to the Holy Grail.

Design and Mechanism

The cryptex is a portable vault for secret information, invented by Leonardo da Vinci and built by Jacques Saunière as a hobby. It consists of six marble disks stacked within a brass framework, each carved with the entire alphabet. The disks rotate around a central cylinder, and when the correct five-letter password is aligned, the cylinder slides apart, revealing a hollow compartment. Inside that compartment, a papyrus scroll is wrapped around a delicate glass vial filled with vinegar. If anyone attempts to force the cryptex open, the vial breaks and the vinegar dissolves the papyrus, destroying the information. The cryptex thus self-destructs if tampered with, ensuring that only the person who knows the password can access its contents.

The Quest for the Password

Saunière's dying message on the Louvre floor includes a scrambled Fibonacci sequence (13-3-2-21-1-1-8-5) and the lines "O, Draconian devil! Oh, lame saint!" Robert Langdon realizes the numbers are a clue to rearrange the letters of those lines, which form an anagram: "Leonardo da Vinci! The Mona Lisa!" This leads Sophie Neveu to the Mona Lisa, where she finds a gold key hidden behind the painting Madonna of the Rocks. The key opens a safe-deposit box at the Depository Bank of Zurich, which contains the cryptex in a rosewood box. The box's lid bears an inlaid rose, and beneath it, a poem in mirror-image English provides the instructions for unlocking the cryptex: "An ancient word of wisdom frees this scroll... and helps us keep her scatter'd family whole... a headstone praised by templars is the key... and atbash will reveal the truth to thee." The poem directs them to find a knight's tomb in London, where the missing orb will reveal the password. Langdon and Sophie, with the help of Sir Leigh Teabing, identify the knight as Sir Isaac Newton, buried in Westminster Abbey. The orb that ought to be on his tomb is the apple that inspired his theory of gravity, symbolizing the fall of the sacred feminine. Applying the Atbash Cipher to the Hebrew spelling of "Baphomet" (a headstone praised by Templars) yields the word "Sophia" (wisdom in Greek), which is the password.

Unlocking and Consequences

Sophie aligns the dials to spell S-O-F-I-A and pulls the cryptex apart. The end cap slides off, revealing a second, smaller cryptex made of black onyx nested inside the first. This second cryptex contains a papyrus scroll with a new poem that points to Rosslyn Chapel in Scotland. When Langdon later solves the second cryptex's password ("APPLE"), he reads the final map, which reveals that the Holy Grail lies beneath the Louvre's inverted pyramid in Paris. The locked state of the cryptex thus functions as a narrative device that structures the entire plot, forcing the characters to decode successive layers of meaning before the secret can be reached.