The Greek military used a form of cryptography by wrapping paper around a staff of wood that when wound tightly would reveal a hidden message. When unwound and during delivery, the text appeared jumbled. What was this form of cryptography called?

A.
Concealment cipher

B.
Skytale

C.
Runic

D.
Purple machine

Explanation:
The Spartans used a "skytale" to encrypt their messages in the 5th
century B.C. Used for military communications, skytale was one of the earliest forms
of cryptography. It is an example of symmetric cryptography because the sender and
receiver need to have the same size staff so when the paper is wrapped about the
staff the letters properly match up.