Columnar Transposition Decoder

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Encode and decode columnar transposition with a key. Ideal for many classic puzzle ciphers.

Plaintext

This page is dedicated to Columnar Transposition Decoder.
Letters only.
Offset shifts the starting zig-zag position before placing the first character.

Ciphertext

Columnar Transposition Decoder — explanation, history & tips

Family: Transposition Era: 1800s–WWII era (variants) Strength: Weak–medium (variant dependent)

Columnar transposition rearranges text by writing it into columns and reading columns in an order determined by a key. Enter your key and this tool will encode or decode immediately, which helps when you’re verifying a suspected transposition key.

  • Pick Encode or Decode.
  • Enter a keyword (e.g. ZEBRAS).
  • The key sets the column order (alphabetical ranking).
  • If it looks close-but-wrong, you may have padding/spacing differences.

History (quick)

Columnar transposition has been used in many historical systems and countless puzzle variants. The key determines column order; with enough ciphertext, patterns and probable words can help recover the key length and ordering.

Quick FAQs

How is the key applied?
Typically columns are numbered by sorting the key’s letters; ties are handled by position order. Implementations vary.
Why do I get slightly different results from other tools?
Padding rules, tie-breaking, and whether spaces are removed can differ between implementations.
How do you break columnar transposition?
Guess key length, use cribs, try common keywords, or use automated scoring/hill-climbing for longer texts.
Want to decode with no key? Try our Cipher Breaker →