The puzzling world of ciphers

By Megan Wang

As someone who loves brainteasers, logic puzzles have always appealed to me. At our most recent FSL session, we had the pleasure to learn about ciphers and try to crack some of our own! We looked at Caesar ciphers (more on that later), but there is still a wide variety of ciphers that we can explore.

What is a cipher?

A cipher (or cypher) is in short, an encoded message. Cipher makers substitute letters and numbers with a variety of symbols. In the past, ciphers were a clever way for people to send secret messages to each other. Nowadays, ciphers are used to help us protect information like our bank accounts and social media passwords. Additionally, the study of ciphers is called cryptography.

In the common vernacular, we often use the words “cipher” and “code” interchangeably. However, the two words actually have very different meanings. A code is used to condense information into a shorter length. For example, hieroglyphs were considered a code in the 18th and 19th centuries because no one knew how to read them. Hieroglyphs usually omit vowels when written, so it fulfills the definition of a code. On the other hand, a cipher is merely substituting symbols with other symbols. Thus, the length of the cipher is not changed.

Caesar ciphers

The Caesar cipher is arguably the most famous cipher and is also the easiest one to crack. When Julius Caesar went on his military conquest, he often coded his messages to his generals so that battle plans would not be leaked to the enemy.

Caesar ciphers are an example of a shift cipher, in which the letters of the code are shifted from the original. Traditional Caesar ciphers are shifted by 3 letters. For example, if your original message was “Hello”, your coded message would read “Khoor”. Modified Caesar ciphers use the same shift technique, but the magnitude of the shift can vary.

Other ciphers to check out

As mentioned at the beginning of the post, there are thousands of ciphers that can be cracked in their own unique way. Below, I have my top 3 favourite ciphers:

1. Dorabella cipher (unsolved) – Written by composer Edward Elgar to his friend Dora Penny, this cipher is composed of 88 mysterious symbols. Numerous people have tried to crack it with no luck.
2. Enigma cipher – This cipher was used by the Nazis in World War 2 for military communication. Thanks to the efforts of Alan Turing and his colleagues, the cipher was cracked. Some estimate that the cracking of the cipher helped shorten the war by two years.
3. Zodiac cipher (unsolved) – This cipher is probably one of the grimmest out there. Coded messages were sent to the authorities by the infamous Zodiac killer, who is still unidentified.