Row-Column Transposition

The Row-Column Transposition cipher writes plaintext into a grid row by row, then reads it out column by column according to a key-defined order. The key determines which column is read first, second, etc.

Transposition ciphers date back to ancient Sparta. The row-column variant became popular in World War I and II for military communications. The German ADFGVX cipher combined substitution with double transposition.

Often used in combination with substitution ciphers for layered security. The concept is used in modern block cipher modes. Double transposition (applying the cipher twice) provides significantly more security.

Single transposition is vulnerable to anagramming attacks. Letter frequencies are preserved, making frequency analysis possible on suspected column lengths. Known plaintext attacks can reveal the key. Multiple encryptions increase security but slow processing.