From Caesar to Polyalphabetic Ciphers: My Fascinating Journey into the World of Cryptography
It was a typical morning, and I had just finished my prayers and confessions when I settled in to watch “House of Dragons”. The show was thrilling, but in the back of my mind, I knew that I had to stay focused on my cybersecurity journey. Specifically, I had to learn more about cryptography, a critical component of the profession.Cryptography aids for confidentiality and integrity of data. This makes it a must for any one breaking into cybersecurity.
With this in mind, I decided to do a quick research on cryptography. I was eager to dive right in, as cryptography is all around us. It plays a crucial role in securing web and wireless traffic, encrypting files, and protecting content on DVDs and Blu-ray disks, as well as providing user authentication.
At its core, cryptography is the study of secure communication techniques that prevent malicious third parties from tampering with messages between a sender and receiver. Cryptography replaces physical locks with virtual ones, known as ciphers. Ciphers allow individuals to encrypt their messages, making them appear meaningless to anyone who intercepts them.
The practice of cryptography dates back thousands of years and has been used to decide wars and establish worldwide communication networks. Julius Caesar used the first known cipher, called the “Caesar cipher”, during his military commands. Caesar shifted each letter in his messages to make them appear meaningless(confidentiality) to any enemies who intercepted them.
To better understand this cipher, let’s use an example. Suppose we want to encrypt the message “MEET ME AT THE ELEPHANT LAKE” using a shift of three to each letter in the alphabet. We would shift the letters forward by three, so M becomes P, E becomes H, and so on. To deciphers the message, we simply reverse the process.
However, modern cryptography requires more advanced techniques, such as the polyalphabetic cipher. This cipher disguises an individual’s fingerprint, making it more challenging for third parties to decipher their messages. To use this cipher, we would need a shift word, such as “snake”. We would convert each letter in the word to its corresponding number in the alphabet and arrange it beneath the message. Then, we would shift each letter forward based on the corresponding number below it. The result is an encrypted message that only someone with the shift word could decipher.
Imagine we want to pass our earlier message “MEET ME AT THE ELEPHANT LAKE” to Mr C and we have a shift word named “snake”. To encrypt this message we first convert the shift word[letter by letter] to it’s corresponding number in the alphabet which is “19,14,1,11,5” then we arrange it under the message to each letter in the word like this;
Then we shift the letters by counting forward according to the numbers below it. That is, after “M” in the alphabet you count 19 times forward,similarly after “E” you count 14 places forward, so M=F, E=S, E=F, T=E which is for “MEET”. Am sure you can carry out the others. Now when this message is sent to Mr C having the shift word, he deciphers it by using the shift word “snake” as reference also like the above this time counting backward such that F, S, F, E becomes “MEET”.
My journey to become a cybersecurity professional has just begun, and I’m excited to learn more about cryptography and its applications in the future. Stay tuned for more on this fascinating subject!
