scytale
A cylinder with a strip of parchment wound around it on which a message is written, used for cryptography by the ancient Spartans.
historical
But, being perſwaded that they would not hear any propoſal to that effect, he delivered each of them a ſcytale, or ſtaff on which the Lacedemonians wrote their ſecret letters, and with theſe diſpatch’d them home to the Ephori.
Where it comes from
From Latin scytale (“cylinder used for encoding and decoding”), from Ancient Greek σκυτάλη (skutálē, “club, baton, cylinder used for encoding and decoding”).
Adapted from the Wiktionary entry scytale (CC BY-SA 4.0).