In 1553, Giovan Battista Bellaso invented an encryption scheme that was considered unbreakable for another 300 years. This method was later misattributed to Blaise de Vigenere, and is thus now known as the Vigenere cipher.
This method is a poly-alphabetic cipher, which means that the same letter may be encoded two different ways at different points in the message. This hides statistical data about letter frequency in the enciphered message. The Vigenere cipher does this by repeating a key word until it matches the length of the plaintext.
Normally, this enables one to look for repeating substrings in the enciphered message to guess at the key word length. Once key word length is known, possible key words can be guessed at, and once one letter of the key word is correct, it will unlock others.
If, however, the keyword is already as long or longer than the plaintext, then the Friedman test must be used to look for characters which have been enciphered using the same portion of the key and guess as to their meaning. The fact that the Friedman test doesn’t work well on short messages provides an additional resistance to cryptanalysis.
Today, this encryption method became printable. Thingiverse user iworkinpixels posted a code wheel which will allow users to encipher and decipher messages using the Vigenere cipher or the Caesar cipher. As an added bonus, he is offering a prize to the first person to successfully decrypt the ciphertext posted on the Thingiverse page!
My dad taught me this cipher when I was a kid, and I’ve wanted for a long time to make a printable code wheel that would allow others to learn the cipher. This is some sort of variant on the Vigenere cipher but I’m not sure of the actual name of this variant, so if anybody knows, please let me know in the comments! I know it is also related to the key autokey and Alberti ciphers.
In addition, I have a prize for the first person to correctly decrypt the ciphertext below and post the plaintext to the comments… I loved the steganography challenge in the Seej block, and it’s high time we had another contest… Good luck!
Oh, and you will find that brute force is not the way to go… there are 1.243841e 142 possible keys. 🙂
UPDATE: There is now a monocase alphas only ciphertext of the same plaintext, which reduces your keyspace down to 4.0329146e 26 possible keys.
[BEGIN CIPHERTEXT]
-G},x3Pp__DPpqSk6’iF5]E0ww”QhV.yEei{b>~wu2)5ecNGGO^AF3w.ur!RE ]E>}.
[END CIPHERTEXT][ALPHAS ONLY CIPHERTEXT]
TKAXPDDFJCJFJIOCXJIIOENGQACFOVDBDFULLYWCFAVYKFOLEWP
[END ALPHAS ONLY CIPHERTEXT]
Every Thursday is #3dthursday here at Adafruit! The DIY 3D printing community has passion and dedication for making solid objects from digital models. Recently, we have noticed electronics projects integrated with 3D printed enclosures, brackets, and sculptures, so each Thursday we celebrate and highlight these bold pioneers!
Have you considered building a 3D project around an Arduino or other microcontroller? How about printing a bracket to mount your Raspberry Pi to the back of your HD monitor? And don’t forget the countless LED projects that are possible when you are modeling your projects in 3D!
The Adafruit Learning System has dozens of great tools to get you well on your way to creating incredible works of engineering, interactive art, and design with your 3D printer! If you’ve made a cool project that combines 3D printing and electronics, be sure to let us know, and we’ll feature it here!
