Scytale Cipher

Scytale Encryption uses a cylinder and a band characterized by its number of turns L of the band around the cylinder.

Example: Code DCODE with a band L=3.

The message is written along the cylinder, one letter per band, and when the end is reached, go to a new line.

If needed, complete the last line with another character, e.g. X or _.

Example:

The ciphered message is the band unrolled, (i.e the message read by column).

Example: The cipher text is DDCEO_

Scytale Decryption requires to know the number N of letters by turn of the band (the size of the cylinder), or L the number of turns around the cylinder.

Example: The ciphertext is DDCEO_ (6-character long) and the band is L=3, then N=2 (because 6/3=2).

Write the message on the band and wraps the band around the cylinder (of correct size) and the plain text should appear.

Example:

To make a real scytale, the parchment ribbon and rolled top-down around a wooden cylinder (a solid stem or a regular wood branch).

The coincidence index is equal to the one of the original text (as it is a transposition cipher).

One can crack Scytale by testing all possible size of the rectangle.

Scytale is a practical application of the Caesar Cipher.

8 to 6 centuries BC