To encrypt messages, John and Jane used Scytale.

$$Scytale is a tool used to perform a transposition cipher, consisting of a cylinder with a strip of parchment

wound around it on which is written a message. The ancient Greeks, and the Spartans in particular, are said

tohave used this cipher to communicate during military campaigns. The recipient uses a cylinder of the

same diameter on which the parchment is wrapped to read the message.