buttcrack. Cipher Wiki

Columnar transposition

From the Buttcrack Cipher Wiki — the free field guide to classical ciphers

Columnar transposition — The plaintext is written into a grid by rows and read out by columns in the order a keyword dictates.

Plaintext written into a grid by rows, read out by columns in key order.

A worked example§

Encrypting a sample with the cipher itself, at build time:

MEET ME BY THE OLD CLOCK TOWER AT DAWN

Key: ZEBRA

produces the ciphertext

MHCTANEYLCEAEBOOWDTTDKRWMEELOT

This example is generated by running the cipher when the page is built, and the round trip is checked, so it always matches what the solver does.

How it is broken§

Anagramming. Score every ordering of the columns by how well adjacent letters form English bigrams, then refine the best.

History and context§

The workhorse field cipher of both world wars, usually applied twice (double transposition) because one pass leaves too much structure.

See also§

Rail fence · Skip / scytale · Route transposition · Myszkowski transposition · AMSCO transposition

Browse every cipher in the Transposition ciphers family, read the history of codebreaking, or return to the wiki main page.

Frequently asked questions§

How is the Columnar transposition broken?

Anagramming. Score every ordering of the columns by how well adjacent letters form English bigrams, then refine the best.

What key does the Columnar transposition use?

keyword or permutation. The keyspace is unbounded in practice.

How much ciphertext do I need?

At least 12 characters for this solver to attempt it; short messages can be readable and still not be proof.

Can I break a Columnar transposition on this page?

Not with the browser build, which targets the common puzzle families. The desktop version searches it: see the Windows app page.

Categories: Transposition ciphers | Full-version ciphers | Cipher wiki
The facts in this article are generated from buttcrack's cipher registry when the site is built, so they describe the implementation you can run on this page. Registry-generated content is checked against the code; the history is editorial.

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