Scytale Cipher

About this calculator

This tool encrypts and decrypts text with the Scytale cipher, one of the oldest known transposition ciphers, said to have been used by Spartan military commanders as early as the 5th century BCE. A strip of parchment is wrapped around a wooden rod of a fixed diameter and the message is written across the wraps; unwound, the letters appear scrambled, and rewinding around a same-diameter rod (the "key") reveals the message again — the digital version uses a chosen number of columns in place of the rod's circumference.

History and cryptography students use it as a hands-on introduction to columnar transposition, the family of ciphers that rearranges letter positions rather than substituting letters. Enter your message and the number of columns (rod diameter) to encrypt or decrypt.