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Scytale transposition

Scytale cipher

Encode or decode text with an exact column key and a reversible preview of the wrapped, ragged grid.

Local processing: your text stays in this browser. This tool makes no network requests and stores nothing.

01 / Workspace

Transpose text

Direction

Encode fills plaintext rows, then reads down the columns.

A whole number from 1 to 5,000. It means characters per plaintext row, not diameter, circumference, or number of rows.

0 / 5,000 code points

Case, spaces, tabs, line feeds, punctuation, emoji, accents, and non-Latin text are preserved as entered.

Ready to encode.

02 / Result

Result

The result contains exactly the same Unicode code points in a different order. No padding is added or removed.

Plaintext wrap grid

Preview limit: 240 cells

Rows show the reconstructed plaintext layout. Scroll sideways when a row is wider than the screen.

The wrap grid will appear after a valid conversion.

03 / Convention

How this version works

  1. Use the key as columns. With key 4, plaintext is written left to right in rows of four characters.
  2. Encode down the grid. Ciphertext takes the first character of every row, then the second character of every row, continuing from left to right.
  3. Leave the last row ragged. This tool never pads. During decoding, the first length mod key columns have one extra character, so the original grid is recovered exactly.
  4. Preserve characters. The route moves Unicode code points without changing case or discarding whitespace. Browser textareas represent pasted CR and CRLF line endings as LF.

Known-answer check

Under this exact convention, ABCDEFGHIJ with column key 4 encodes to AEIBFJCGDH. Decoding that ciphertext with key 4 returns ABCDEFGHIJ.

A B C D E F G H I J

Limits and security

  • Input is limited to 5,000 Unicode code points and 10,000 UTF-16 code units. The key is limited to 5,000 columns, and the visual preview is omitted above 240 cells.
  • A key of 1, a key equal to the text length, or a key larger than the text length produces unchanged text. These are valid but provide no transposition.
  • Some scytale tools define the key as circumference or row count, and some add padding. Results from those conventions may not match this tool.
  • Scytale is a classical cipher for education and puzzles. It is not secure and must not be used to protect sensitive information.