Tool to decrypt/encrypt with Monome-Dinome cipher a Polybius square variant using coordinates in an incomplete grid.
Monome-Dinome Cipher - dCode
Tag(s) : Substitution Cipher
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The monome-dinome cipher (or monome-binome) is a substitution cipher according to the coordinates of a grid (from the family of the Polybius square). Its characteristic is described in its name: certain letters are coded either by a monome (1 single digit) or by a dinome (2 digits).
Monome-Dinome is compatible with several types of deliberately incomplete grids with at least 2 special columns which will be used as the header name for the following rows.
— Variant 1: a 3x10 grid with 2 empty squares on the first row.
Example: Grid with the keys of rows 3 and 7:
\ | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |
---|---|---|---|---|---|---|---|---|---|---|
A | B | C | D | E | F | G | H | |||
3 | I | J | K | L | M | N | O | P | Q | R |
7 | S | T | U | V | W | X | Y | Z | ␣ | * |
NB: 28 characters are possible, generally the 26 letters from A to Z, a space and a special character like *
— Variation 2: a 3x8 grid with missing columns.
Example: Grid with the keys of rows 3 and 7:
\ | 0 | 1 | 2 | 4 | 5 | 6 | 8 | 9 |
---|---|---|---|---|---|---|---|---|
A | B | C | D | E | F | G | H | |
3 | I | K | L | M | N | O | P | Q |
7 | R | S | T | V | W | X | Y | Z |
NB: only 24 characters are possible, generally J is replaced by I and V replaced by U
Monomial-binomial encryption consists in replacing each letter of the plain message by its coordinates in the grid.
Grid coordinates are read as [row,column]. The first row having no name, the coordinates are formed only from the name of the column.
Example: MONOME is coded 34,36,35,36,34,5 (3x10 grid)
Monome-binomial decryption consists of reading the numbers which are the coordinates of the letters in the grid.
Take the first digit N, if it is not a row number, then the plain letter is on the first row, column N. Otherwise, take the second digit M and the plain letter is row N, column M.
Example: 4303536345 splits 4,30,35,36,34,5 and translates to DINOME (3x10 grid)
The text encoded by monome-binome is composed of digits.
The 2 digits representing key columns/rows are usually over-represented in frequency analysis.
The grid can/must be generated from a keyword in order to obtain a disordered alphabet.
The order of the columns can also be modified from a keyword in order to make a permutation.
The creation date of monome-binome is not known. There are historical traces of the use of this cipher during the Spanish Civil War in 1936.
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Cite as source (bibliography):
Monome-Dinome Cipher on dCode.fr [online website], retrieved on 2024-12-03,