Information desk
About this station.
Plaintext is a history of secret writing told as a departure board: 18 ciphers, from a folded alphabet in ancient Jerusalem to the fingerprints that guard your passwords, each with a machine to work and a message to break.
How it works
Every cipher has its own platform. The machine at the top of each one is a working model: turn the disk, wind the strip, press the keys. Below it an intercepted message arrives on the board, and you break it with the method that broke the real thing, from simple patience to counting letters, finding repeats, sliding a guessed word along or factoring a number. Hints are there if you get stuck; the last one always gives the answer away.
When you crack a cipher its status on the departures board turns green. That is remembered in your browser only (local storage), so another device or a cleared browser starts from an empty board. "Lock it again" on any platform resets that one puzzle.
Codes and ciphers
Strictly, a cipher works on letters (or bits) and a code replaces whole words or phrases. Most of this board is ciphers. The nomenclator sits between the two, and the code talkers' platform is a true code.
What is drawn, and what is real
Every machine on the site is drawn and run in code, from historical descriptions rather than photographs: they are models, not replicas of any one surviving object. The Enigma follows the real wirings of the army machine; the hash platform uses your browser's own SHA-256. The intercepted messages are our own, written for the puzzles.
Facts were checked against the sources below in a separate pass. Where historians disagree (whether the scytale was really a cipher, who invented what first) the text says so. If you spot a mistake, it is ours.
Sources
David Kahn, The Codebreakers (1967, revised 1996); Simon Singh, The Code Book (1999); Craig Bauer, Secret History: The Story of Cryptology (2013, 2nd ed. 2021); the primary texts named on each platform (Suetonius, Plutarch, Polybius and others); NIST FIPS 180-4 for SHA-256; the National Cryptologic Museum and Bletchley Park Trust publications.
Credits
Type: Oswald by Vernon Adams and Inter Tight by Rasmus Andersson, both under the SIL Open Font License. Sounds are synthesised in the browser. No photographs, no ads, nothing for sale.
Plaintext is one of the encyclopedias of Whyarium, a set of hobby sites made for the joy of it.