Puzzle & Novelty Ciphers
Cryptographically weak. Historically fascinating. Explore encoding, concealment and communication.
Not every cipher was designed to win wars or protect state secrets. Some were tools of secret societies, some were intellectual exercises, and one was the difference between isolation and survival for prisoners of war. This hall honors ciphers whose significance lies not in their cryptographic strength but in their human story.
Looking for the museum's open mysteries? The major unsolved historical exhibits that once crowded this hall — Voynich, Beale, Dorabella, and Kryptos — now live together in Hall XII: Unsolved Ciphers, where the museum can present them as active research problems rather than novelty pieces.
Bacon’s biliteral alphabet represents letters by patterns of two forms and can hide them in a carrier. That is a useful early example of binary representation, but it does not establish a direct historical line to Shannon’s information theory or electronic computing.
Pigpen cipher (~1700) — Freemason geometric substitution where each letter becomes the lines and dots of its grid cell. Trivial once the glyph table is seen.
Bacon’s biliteral alphabet represents letters with patterns of two forms and can hide them in a carrier. Binary representation is distinct from a direct historical origin for ASCII.
Tap Code (1965) — the 5x5 Polybius square tapped through walls as row-then-column knocks. Used by US POWs in the Hanoi Hilton during the Vietnam War.
Zodiac killer ciphers (1969) — homophonic substitution as in Z-408 (broken in 1969 by the Hardens) and Z-340 (broken in 2020 by Oranchak, Blake, and Van Eycke).
Knight, Megyesi and Schaefer deciphered the Copiale manuscript in 2011 using transcription, statistics and manual analysis. The exhibit separates that result from its invented demonstration alphabet.
Equidistant-letter claims require controls for flexible search choices. McKay and colleagues examined the statistical experiment and showed how alternative name choices produced striking results in a control text. The Moby-Dick demonstrations were a separate challenge to prophecy claims.
The Tap Code's real value: Every guard who knew the pattern could intercept tap code messages. The system was not cryptographically secure. But that wasn't the point. The Tap Code's value was human — it maintained communication, solidarity, and command structure among men in solitary confinement. Sometimes a cipher's purpose is not secrecy. It's connection.