Myszkowski

History

Developed by the French Colonel Émile Victor Théodore Myszkowski and described in his book Cryptographie Indéchiffrable published in 1902 the Myszkowski cipher is a transposition type using a keyword to rearrange the plaintext.

Description

The cipher is created by selecting a keyword with repeated letters and writing the plaintext in a block below the keyword. The keyword is converted to a number by numbering the letters in alphabetical order with identical letters having the same number. Using the example below with the keyword MAMMAL the first alphabetical letters A are replaced by the number 1, the next letter L is replaced by 2 and so on to produce the key 313312. The ciphertext is produced by reading the letters by row, first all the letters under the number 1, then all letters under 2 and so on.

Example

Key: MAMMAL

Plaintext: The trouble with doing something right the first time is that nobody appreciates how difficult it was.

MAMMAL

313312

THETRO

UBLEWI

THDOIN

GSOMET

HINGRI

GHTTHE

FIRSTT

IMEIST

HATNOB

ODYAPP

RECIAT

ESHOWD

IFFICU

LTITWA

S

Ciphertext: HRBWH ISEIR HHITM SAODP EASWF CTWOI NTIET TBPTD UATET ULETD OGOMH NGGTT FRSIE IHTNO YARCI EHOIF ILITS

Solving

Solving methods: Brute force and Dictionary keyword search.

After selecting the Myszkowski cipher, the cipher period can be selected from the Setup drop down menu. If solving using the dictionary keyword search the default setting of 0 will result in all periods in the keyword range set in the Options window being tested. The brute force search requires the key length to be set.