Whenever I learn something, I always try to implement it in a more familiar space, so as to give context to understand it better. In this case, I am implementing concepts from Cryptography into Python to understand it better.

For those of you who are familiar with Python, I hope that you can learn a little bit of Cryptography from this article and for those of you who are familiar with Cryptography, I hope you can learn some a Python. For those who are nor familiar with Python, I envy you as this is the perfect learning opportunity to learn about both at the same time.

Ciphers:

Ciphers are the backbone of Cryptography, the foundation of how messages can be encoded so as for the true message to be transmitted for those who it was intended to. I find this fascinating because before this, one could have only used physical means to hide information from others.

A cipher functions as so:

Cipher(Plaintext) = Ciphertext

The Cipher is a function that encodes the message so that the original text cannot be derived from the Cipher-text directly.

To get from the Ciphertext to the Plaintext:

Plaintext = Cipher^-1(Ciphertext)

We have to take the inverse of the Cipher function to reach the original message.Let’s look at one type of cipher:

Caesar Ciphers:

In a Caesar Cipher, we are shifting the alphabet forward or background by a factor of n.

For example, if n = 1, A becomes B, B becomes C, C becomes D and so on. Let’s construct an algorithm for this.

First we want to create a class for all the ciphers:

class ciphers:
    def __init__(plaintext):
        self.plaintext = plaintext

Next we add the Caesar Cipher:

def caesar(self,n):
        words = self.plaintext.split()
        alpha = []
        indexes = []
        ciphertext = []
        letters = string.ascii_letters[:26]
        for i in range(len(letters)):
            alpha.append(letters[i])
        for word in words:
            for letter in word:
                index = alpha.index(letter)
                new_index = index+n
                if new_index > len(alpha):
                    new_index - 26
                indexes.append(new_index)
        for index in indexes:
            ciphertext.append(alpha[index])
        ciphertext = ''.join(ciphertext)
        return ciphertext

#python #cryptography #programming #coding