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Classic Cipher Disc
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Classic Cipher Disc

Watermarked PDF

Printable Cipher Disc

Cipher Disc

Those secret messages your players intercept should be secret! While this is particularly true in espionage or horror games, in different forms they fit into just about every genre, because there are always secret texts to read, whether they're messages to spies, clues to a treasure, or the writings of demented cultists. This Cipher Disc makes it easy! Naturally Wintertree Software sells a program to handle this, CRYPTER, and some interesting cipher fonts, but there's always the old-fashioned way: a cipher disc. And if you're playing an escape room and suspect they'll have encrypted messages for you to solve, it fits in your pocket.

We're talking seriously old-fashioned here: The device dates back to at least the 15th century. The concept is simple but elegant: You turn the inner disc so the alphabets line up as desired, and then just find the letter you want on the inner disc and read off its counterpart on the outer disc. Simple, really -- but with it, you can do not only simple letter-shift ciphers like the Caesar cipher, but Vigenère and even autokey ciphers. (though CRYPTER does them instantly) This little device, made in everything from cardboard to metal, revolutionized cryptography. It was used extensively in the American Civil War, and in some form up until the 1930s, and even after that as the "Captain Midnight Secret Decoder" and similar premiums.

To promote CRYPTER, Wintertree made up a do-it-yourself cipher disc to hand out as a flyer. This is it, free for download. Print out the page on the heaviest cardstock your printer can handle (or on something lighter, then glue it to cardboard for strength). Punch a hole in the designated spot in the center of each disc. Put the smaller one on top of the larger one, fasten them together with a brad, paper fastener, or similar thing that allows the inner one to rotate separately, and you're ready to go. Instructions for using the cipher disc to encrypt and decrypt the Caesar and Vigenere ciphers are on the page.

Captain Midnight decoder badge

The Captain Midnight Secret Decoder Ring

It's not just a meme! There really was such a thing as a Captain Midnight Secret Decoder, though it wasn't a ring. (usually, it was a badge) The secret decoder was a premium given out to listeners of the highly popular radio show in exchange for some number of Ovaltine labels and a small fee, and used by the listeners to decode secret messages given by the show's announcer.

The picture to the left is an actual Captain Midnight's Secret Squadron Mirro-Flash Code-O-Graph from 1946, from the author's collection. The central silvery nub is supposed to act as a signal mirror. Yes, they were maybe sligtly overblown with the names!

As you can see, there are two discs, the outer one fixed and the inner (red) one movable. It's nothing more or less than an Alberti cipher disc! The outer disc has the alphabet in scrambled order (it was different for each year's disc, so the kids would have to drink more Ovaltine to get the current one), and the inner one has the numbers from 1-26. The user turned the inner disc to the designated setting -- exactly how that was selected differed by year, ranging from numbers visible through holes in the back to a letter/number pair announced along with the secret message. Then, when the listener copied down the series of numbers that constituted the secret message on the show, they could use their secret decoder to read the message.

The font used for the title text in the product graphic is Remington, from The Vaults of McTavish.

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0.6 MB
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These products were created by scanning an original printed edition. Most older books are in scanned image format because original digital layout files never existed or were no longer available from the publisher.

For PDF download editions, each page has been run through Optical Character Recognition (OCR) software to attempt to decipher the printed text. The result of this OCR process is placed invisibly behind the picture of each scanned page, to allow for text searching. However, any text in a given book set on a graphical background or in handwritten fonts would most likely not be picked up by the OCR software, and is therefore not searchable. Also, a few larger books may be resampled to fit into the system, and may not have this searchable text background.

For printed books, we have performed high-resolution scans of an original hardcopy of the book. We essentially digitally re-master the book. Unfortunately, the resulting quality of these books is not as high. It's the problem of making a copy of a copy. The text is fine for reading, but illustration work starts to run dark, pixellating and/or losing shades of grey. Moiré patterns may develop in photos. We mark clearly which print titles come from scanned image books so that you can make an informed purchase decision about the quality of what you will receive.
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Watermarked PDF
Watermarked PDF

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File Last Updated:
January 16, 2018
This title was added to our catalog on January 17, 2018.