Secret Decoder Ring – Caesar Cipher Medallion (Little Orphan Annie Style)

Authentic Retroworks
Caesar Cipher Medallion
The top ring rotates around the bottom one, setting your secret code
number in the window.
To use this ring, think of the inner disk as the
true message and the outer disk as the encoded message. The numbers in
the square window of the inner disk represent the code shift of your
message.
If you set 1 in the window, there is a shift of 1, and “A”=”B”,
“B”=”C” and so on.
To encode a message, first choose your secret code
shift number. Let’s use 17 for an example by turning the inner disk
until 17 is seen in the window. To encode “HELLO” you look across from
“H” on the inner disk and see “Y” on the outer disk. Across from “E” is
“V”, “L”=”C”, “L”=”C” again, and “O”=”F”.
So with a code shift of 17,
HELLO is encoded to YVCCF. The recipient of a message must know the code
shift number to decode a message.
Let’s decode XPDDLRP. We have no idea
what it says, but if we know the code number is 11, we can set that in
the window. We decipher code from the outer ring to the inner. Across
from “X” is “M”, across from “P” is “E”, “D”=”S”, “D”=”S” again,
“L”=”A”, “R”=”G”, and “P”=”E”.
So XPDDLRP decoded with a shift of 11 is
MESSAGE.