DAILY TRAFFIC
The cipher room
Twenty classical ciphers, each with a working bench tool, a written deciphering walkthrough, and the weakness that ended it. One cipher of the day, chosen by the date.
TODAY'S TRAFFIC — MODERN / POLYALPHABETIC
PINOV NX
Rotors I II III, ring and start positions all at A, no plugboard. Remember the right rotor steps before the first letter.
Plaintext
LOOMKEY
How this loom is strung
Every entry follows the same six stages: the phenomenon you can see, the key space and what it is really worth, the enciphering steps, the deciphering steps, the weakness, and a practice challenge you can check.
The bench tool beside each cipher is real code running in your browser. Nothing is sent anywhere, and the source is a single readable file — view it and check the implementation against the description.
Ciphers on the loom
17 / 20Antiquity
5Tironian Notes
Before ciphers abbreviated letters, they abbreviated *words*. Tironian notes were a Roman shorthand of several thousand signs…
[THE] (SCRIBE) (WROTE) [CON] [AND] [EST] (IN) …
Antiquity · Substitution · StarterPolybius Square
Polybius did not invent a cipher. He invented a *notation*: a way to write any letter as two numbers between one and five. That…
32 35 35 33 34 15 52 15 43 44 45 35 41 44…
Antiquity · Transposition · StarterScytale
The scytale does not rename letters — it shuffles them. Wind a strip of leather around a wooden staff, write across the turns…
TOESP EHOAA AREMV LTNLW ELTS…
Antiquity · Substitution · StarterAtbash
Atbash folds the alphabet in half and glues A to Z, B to Y, C to X. There is no key at all — knowledge of the method is the whole…
ZMWGSVOLLNRHGSVPVB…
Antiquity · Substitution · StarterCaesar Shift
The oldest alphabet cipher most people meet first: every letter moves a fixed number of places down the alphabet. It takes about…
WKHROGORRPQHYHUVWRSV…
Medieval
4Book Cipher
A book cipher replaces the alphabet with a book. Every letter is written as a position — page, line, word, letter — and the…
1 2 3 29 11 11 19 8 3 3 20 21 6 1 21 11 12 13 …
Medieval · Substitution · FieldNull Cipher
A null cipher does not disguise a letter — it hides which letters are the message. Every character in the transmitted text is a…
THEWL ATHEO HOLDO FAIRM NDTHS OLDBK ASSLE OMKE…
Medieval · Substitution · FieldNomenclator
A nomenclator is half cipher, half dictionary. It substitutes letters as usual but also assigns its own codes to the names that…
01 / 03 / 02 / 01 / 04…
Medieval · Substitution · StarterPigpen Cipher
Pigpen writes letters as fragments of a grid. Two tic-tac-toe frames and two X frames give exactly 26 cells, so the cipher fits…
N3 N5 S3 S3 E1 N8 S6 S3 N4 E1 N5 N3 S9 N5 E2 E…
Renaissance
6Baconian Cipher
Francis Bacon's 1605 biliteral cipher is the first recorded binary encoding of an alphabet, three centuries before anyone had a…
BAABA AABBB AABAA ABABA ABBAB ABBAB ABABB BAAA…
Renaissance · Transposition · FieldColumnar Transposition
Columnar transposition is the workhorse of classical field ciphers: simple enough to do with a pencil, strong enough to be worth…
OEP LET OVO MRS NSX…
Renaissance · Transposition · FieldCardan Grille
Girolamo Cardano's grille is a sheet of stiff paper with holes cut in it. Lay it over a blank page, write the message through the…
· S · · E · · C · · R · · · · · · · E · · · T …
Renaissance · Polyalphabetic · FieldPorta Cipher
Giovanni Battista della Porta published this tableau in 1563 and solved a problem that had annoyed cryptographers for a century…
AAAANZSVJFWOPY…
Renaissance · Polyalphabetic · FieldAlberti Disk
Leon Battista Alberti built a brass disk in the 1460s and, with it, crossed the line that separates classical from modern…
TEAR HTKU WTOU…
Renaissance · Polyalphabetic · FieldVigenere Tableau
The Vigenere cipher was called *le chiffre indéchiffrable* — the indecipherable cipher — for roughly three hundred years, and the…
UYEDGPDRWEFDBWJT…
Modern
2Enigma Rotor Machine
Enigma is the cipher that looks unbeatable on paper and lost a war in practice. Its key space was in the hundred-sextillions and…
PINOV NX…
Modern · Substitution · FieldPlayfair Square
Playfair was the first practical cipher to encrypt letter *pairs* rather than single letters, and that one design decision bought…
JSVSGTIYCFTNQIXH…
Progress: 0/20 solved