Secret and Cypher (SW)

From publisher blurb:

Secrets are valuable. Knowing the enemies’ orders can win a war. Knowing a competitor’s recipe for superior steel can make you rich. As long as there have been people, there have been secrets. The trouble is that sometimes you need to share these secrets, but only with a certain few.

That is why humans invented ways to hide secret messages, an art known as steganography. Of the many ways to hide messages one of the most popular is cryptography, the means of turning messages into unreadable blobs of text and then back.

Secret and Cypher includes:

A real world history of cryptography
Optional rules for encoding and decoding message
New equipment
1 new power
2 magic items
3 new monsters