Decoder
Examples: COL or 1,3,2. Duplicate letters use stable left-to-right ranking.
Short-key helper only: at length 7 it tests 5,040 arrangements.
CRYPTOGRAPHY / TRANSPOSITION CIPHER
Reorder columns with a keyword or numeric permutation, inspect the grid, and brute-force short keys.
Short-key helper only: at length 7 it tests 5,040 arrangements.