# Vigenère Squares [56] ramblings of a deductionist

[none of the pictures on my blogs are mine by the way]

# Topics of Discussion:

Vigenère Squares and How They are Used

Reminder

Challenges

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# Vigenère Squares and How They are Used

The cover image for this blog is a vigenère square. Vigenère squares are one of my favorite codes to play with both coding and decoding. It is a very interesting code and if you don’t know how to use it and show someone the square, it genuinely confuses people which is always fun.

Vigenère squares were introduced in 1553 and were declared unbreakable until 1863. The square that is seen and used today is just one of many ways that people applied this same method of coding and switching through cipher alphabets throughout history. This cipher has been used in wars and for other forms of encrypted message sending.

This square, instead of using one or two alphabets to encode, uses 26 different cipher alphabets. This makes the decoding process extremely difficult without a key. Each alphabet represents a Caesar shift cipher of one place and you use all of the alphabets to encode messages. This code works by key word. You will choose a key word then repeat that key word however many times it takes you to complete the message you are trying to encode. Let’s look at an example.

Let’s use the key word “cipher” and encode the message “deduction is cool.”

The encoded message would read like this: FMSBGKKWCPWTQWA

How that you have an example, I’ll explain how that was done.

The top alphabet that goes from left to right at the top of the square is the plain text alphabet. This is the alphabet where you will look for the letters in the messages you want to encode. So for application of the above example you would look for “d” and then “e” and so on in that top alphabet. The first alphabet that is listed vertically on the left side is your cipher text alphabet. This is where you go to locate the letters for your keyword. So for application of the above example you would look for “c” then “i” and so on. The key word is repeated however many times it takes to encode the entire message you want to encode. Here is another image of the square with the alphabet codes:

To encode the message you locate the first letter of your plaintext on the plaintext alphabet, locate the first letter of your key word in the cipher text alphabet and cross reference the two. So for the above example, I would first locate the letter “d” in “deduction” and go down in the alphabet beneath the letter “d” until I reached the alphabet that starts with “c” in the cipher text alphabet. This meets up and gives you your first encoded letter, “f.”

This link gives you a good visual representation of the cross referencing encoding process for those still lost: https://docs.google.com/spreadsheets/d/13VnNwrQ9-45mT0ERBc5EW_kFsdOGPBuAQqezguR5HYU/edit#gid=0

You might see why I find this cipher so interesting and enjoy playing with it yourself. I find it interesting because of the combination of complexity and simplicity. If you know the key, you can decode and encode messages easily. However, without the knowledge of a key, it is pretty difficult to decode.

If you want to know how to decode a vigenère cipher without knowing the key I will refer you to this video: https://youtu.be/LaWp_Kq0cKs

Generally, the video shows you how you can find which shift alphabet is used for each letter of the key, therefore finding the key. This requires knowing the letter frequencies in your language and applying some math which I will not explain here. The video gives a good, straightforward explanation of how to determine the length of the key and the alphabet that the key letter is located in and explains it much better visually than I could with words through my blog. There is a link to the English letter frequencies in the description of the video and you can determine which cipher text/ key word alphabet is used by the numbered alphabet at the bottom of the screen. However, the likelihood that you would have to decode this form of cipher by hand without knowing the key is unlikely. There are several tools on your computer that you can use to do the math for you so you don’t have to do it by hand.

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# Reminder

I included this in my last blog but I thought another reminder of how this is related to deduction would be good.

Practicing codes and ciphers might not be the first thing you think to do when looking to improve on your deduction skills. However, as I stated in a previous blog, the mindsets used to solve this can be easily transferred to application in your deduction mindsets. It teaches you to think outside the box, look at everything, and pay attention to detail… all of which are skills needed to succeed in the practice of deduction as well! It is important to branch out and have fun with your training, which includes doing exercises such as these. This could also provide something fun to get you motivated if you have found yourself not wanting to put time into your training. Doing puzzles like this always get me excited about training other topics as well. Let them get you excited about applying those similar mindsets to deduction!

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# Challenges

No one has decoded the challenges from my previous blog so I will include them here as well!

I want to give you a few challenges that incorporate this blog’s topic as well as topics from the previous code and cipher blogs. Decode the messages for practice!

Challenge 1:

Igt eua lomaxk uaz cngz zevk ul iovnkx znoy oy ktiujkj cozn? Cngz cgy znk tgsk ul oz? Nuc ngy znoy skyygmk hkkt ktiujkj?

Challenge 2:

Ru blf szev urtfivw lfg gszg gsrh rh z hfyhgrgfgrlm xrksvi, xzm blf urtfiv lfg dszg rh hkvxrzo zylfg gsv hfyhgrgfgrlm zokszyvg?

Challenge 3:

. — . — .- .- ……. -..- …. . . — . — .. — ……. .- …. — -..- ……. -..- -.-. — . ……. — .- ..-. ……. — .. — …- .. — -..- .. — .- . — . ……. .-. .. — …. . …- ……. .. . — ……. -..- …. .. . — .. — .. ……. … .. … ……. -.-. — .- -. — ……. ..-. .. . — . … ……. -..- …. . ……. .-. — .- … . ……. .- — .- …- … .. — .. ……. .-. — . — . ……. -.-. — .- -. — ……. … . .-. — .- … . ……. -..- …. . ……. -. — .- …- . — . ……. .-. — .- … . ……. -..- — .- ……. ..-. -. — …- -..- …. . …- ……. … . .-. — .- … . ……. -..- …. . ……. . . — . -..- .. …- . ……. -. . . — . — — — . . .. — ..

Challenge 4:

… .. . … ….. … .. …. ….. …. . ….. ….. … ….. …. .. .. . … ….. ….. ….. ….. ….. . .. …. .. .. …. .. . … . …. .. .. . … . … … … …. … . … … .. . ….. . … . … … …. … … …. … ….. … . …. …. .. …. … . … … . ….. . ….. …. …. . . … . … .. .. … …. ….. . ….. . . … . … ….. ….. . .. … …. .. . …. … ….. …. . ….. . … … . ….. . ….. …. …. . . … …. … ….. … ….. …. . .. … … … …. . .. . …. ….. …. … … … …. … .. ….. …. … … … …. . …. …. .. …. … . … ….. .. … …. . … . … . … …. . … ….

If you send me a message showing that you have decoded all four challenges (send me the decoded messages) then I will let you pick my brain about any topic (relating to my blog and the topics covered here) that you like! You can ask me any question or for any advice or tips related to deduction you would like and I will give you as much time as you would like to chat!

You can either send things directly to me on instagram (@ramblings.of.a.deductionist) or tumblr (ramblings-of-a-deductionist) or to my email (ramblingsofadeductionist@gmail.com).

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# Next Blog: The Enigma Machine

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Disclaimer:

I teach people inductive/deductive reasoning and related topics. Most of the information on my blog comes from my own experiences and observations but some of it will also come from various different sources and is just information I use. I don’t claim ownership of information from other sources.

I have been studying these mindsets religiously for a while now and have been practicing memory techniques since I was in the sixth grade. However, I too am still learning. So if you have any suggestions or comments that are helpful to others that I neglect to mention please do so in the comments. I do not claim to know everything there is to know about these techniques. This blog is for educational purposes for me and the readers.

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There are several books on the topics which I cover in my blogs. I can send you my working book list if you would like to read them. If you are interested message me.

Also, if you want a source for daily deduction practice material message me.

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## rolling wind

I run the Ramblings of a Deductionist publication where I teach deductive/inductive reasoning skills and discuss related topics.