Myszkowski Transposition
Repeated keyword letters change the route: tied columns are read together across rows
Repeated-keyword transposition preserves letter frequencies and is vulnerable to statistical and keyword-search attacks.
The standard repeated-rank convention, with incomplete final rows and no padding. A keyword without repeats reduces to ordinary columnar transposition. The demo uppercases letters, removes accents, and discards spaces, punctuation, and digits.
Why This Matters
Most columnar transposition implementations break ties between repeated key letters from left to right. Myszkowski assigns those letters the same rank. That one change turns a set of separate columns into a group read across each row, making repeated letters part of the permutation instead of an inconvenience to resolve.
Myszkowski published Cryptographie indéchiffrable in Paris in 1902. The title’s claim of indecipherability did not make the system secure. The exhibit follows the repeated-rank convention documented by the American Cryptogram Association: write the message by rows; read single columns downward and tied columns together across rows.
Like other hand transpositions, the method changes positions rather than letter identities. It offers a compact lesson in how a key and an exact tie rule determine a reversible permutation.
Sort the distinct letters of the keyword alphabetically and number them. Every occurrence of the same letter receives the same rank. With TOMATO, A = 1, M = 2, O = 3, and T = 4, giving 4 3 2 1 4 3.
Write the message in rows six letters wide. Read rank 1 down its column, then rank 2. For rank 3, read both O columns from left to right in each row before going to the next row. Do the same for the two T columns at rank 4. Skip missing cells in an incomplete final row.
Key: T O M A T O
Ranks: 4 3 2 1 4 3
W E A R E D
I S C O V E
R E D F L E
E A T O N C
E
Rank 1: ROFO
Rank 2: ACDT
Rank 3: EDSEEEAC
Rank 4: WEIVRLENE
Output: ROFOACDTEDSEEEACWEIVRLENETo decrypt, construct the same occupied cells from the ciphertext length and keyword width. Fill them in rank order using the same tie rule, then read the restored grid by rows. This demo does not add padding, including when the final row is short.
For ordinary columnar transposition, repeated letters usually receive separate positions; TOMATO would have ranks 5 3 2 1 6 4. Myszkowski’s ranks are 4 3 2 1 4 3. The difference is visible in the demo’s grid header.
With a keyword containing no repeated letters, the two routes agree under the same no-padding convention. Try ZEBRA here and in Columnar Transposition to study how a tie rule changes the cipher rather than the underlying message.
The cipher preserves single-letter frequencies. A suspected keyword width gives a candidate grid shape; probable words and neighbouring-letter scores constrain which positions should become adjacent. Dictionary searches can try likely keywords, while broader searches can score candidate rank patterns directly. A keyword that is easy to remember may also be easy to guess.
This is a broken classical transposition method for study and puzzles. Neither repeated ranks nor the 1902 book’s title provide modern confidentiality. It supplies no integrity check: rearranging the ciphertext can also rearrange the recovered text.
| Exhibit | 164 of 167 |
| Origin | Émile Victor Théodore Myszkowski |
| Year | 1902 |
| Family | Keyword transposition |
| Key | A word with repeated letters |
| Example | TOMATO → 4 3 2 1 4 3 |