The postponed and long-awaited cipher challenge is finally here! I recommend you guys work in groups or as a class for this to save some time.
In case you don’t know, a cipher is a disguised way of writing — it’s an encoded message. This challenge isn’t directly related to Leonardo da Vinci (though he did use mirror-writing and was pretty secretive about his notes, so it’s not entirely unrelated either), but I think it’s an interesting (and fun, if you like puzzles) way to practice looking at things differently! It all leads to becoming more creative. So, let’s get started!
One of the earliest and simplest forms of encryption is something called a Caesar/shift cipher. It’s about what you’d expect from the name. Here’s an example:
Let’s say you want to encode this message: Leonardo da Vinci was a cool dude. With a Caesar cipher, you’re “shifting” the letters a certain number up or down the alphabet. So, to keep things simple, let’s say we want to use a right shift of two. Therefore, A=C, B=D, C=E, D=F, and so on.
With a right shift of two, “Leonardo da Vinci was a cool dude.” becomes “Ngqpctfq fc Xkpek ycu c eqqn fwfg.” You know you’re on the right track when it looks like a lot of gibberish.
This type of cipher is easy to decode because all of the words stay intact, and one can easily just use brute force to go through all possible combinations. It might be a little dull and time consuming, but you can get the answer eventually. A good technique is to think of some of the most frequently used letters in the English language (e, a, r, i, o, and so on) and try to find a pattern in the encryption by looking at the most common letters. You can also look for words that are 1-3 letters because those are fairly easy to match up.
If you’d like to practice, here are some encrypted messages using a Caesar cipher that you can try out:
- Gwadzwqwhm wg hvs izhwaohs gcdvwghwqohwcb.
- D cvqz vgrvtn azgo do dn ht yznodit oj wpdgy v hvxcdiz ocvo rjpgy vggjr hvi oj agt.
- Zk yru cfex jzetv tfdv kf dp rkkvekzfe kyrk gvfgcv fw rttfdgczjydvek irivcp jrk srtb reu cvk kyzexj yrggve kf kyvd. Kyvp nvek flk reu yrggvevu kf kyzexj.
If you think you’ve got it, feel free to skip these and move on. They’re all quotes by a certain Renaissance man, if you’re curious.
Another interesting type of cipher is the transposition cipher. It’s a lot less straightforward because it doesn’t use substitution. Let’s take our example from earlier, “Leonardo da Vinci was a cool dude.”, and I’ll try to explain it.
First, we’re going to remove the capitalization, punctuation, and spaces, which leaves us with “leonardodavinciwasacooldude”. It’s important to note that we have 27 letters here because now we’re going to write the message in three rows composed of nine letters each, like this:
l e o n a r d o d
a v i n c i w a s
a c o o l d u d e
From that, we finish the encryption by reading the letters in order down the column to get “laa evc oio nno acl rid dwu oad dse” and then removing the spaces “laaevcoionnoaclriddwuoaddse”. As you can see, it’s a lot more intimidating.
So, how do you solve it? Well, it involves a little math.
First, you’ll want to count up the characters. We have 27. 27 characters can be encoded in grids of 1×27 and and 3×9. A 1×27 grid is just going to look like the original message, “laaevcoionnoaclriddwuoaddse”, so that’s not helpful. Therefore, it has to be a 3×9 grid. Just write the first three letters down as a column, the next three as the adjacent column, and so on. This particular message was pretty easy!
But, it’s not always going to be simple like that. You might get a message with 24 letters, which could make grids of 1×24, 2×12, 3×8, and 4×6. In that case, you’d have to try writing all possible grids until you get to the one that spells everything out correctly!
Here are some examples for you to try:
- cnosnygotuastoullvaetdiiot (26 characters)
- ioaihunnohagpamdevaavezy (24 characters)
- ryoeteahvlieinrzgyecttohhnianntegecevtlessrte (45 characters)
That’s all I have time to write for today unfortunately — I hope these didn’t turn out to be too tedious. Best of luck solving them!
The examples here were mainly meant as short practices to learn different cipher techniques. I would’ve liked to write a more in-depth post with a compound cipher or something at the end (a cipher using multiple techniques), but fourth quarter has started off pretty strong for me so there’s not as much time to write. 😦 If you’d like, feel free to check back tomorrow because I’ll probably edit this post and add more content later today! I really want to try my hand at creating a compound cipher of some kind because I think it’d be fun for classes to collaborate on and solve.
Until then, happy decoding! See you again tomorrow or next week. 🙂
