Code for How to Implement the Caesar Cipher in Python Tutorial

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caesar_cipher.py

import sys # The sys module for system-related operations. from colorama import Fore, init # Import the colorama for colored text init() # Initialize the colorama library for colored text. def implement_caesar_cipher(message, key, decrypt=False): # Initialize an empty string to store the result. result = "" # Iterate through each character in the user's input message. for character in message: # Check if the character is an alphabet letter. if character.isalpha(): # Determine the shift amount based. i.e the amount of times to be shifted e.g 2,3,4.... shift = key if not decrypt else -key # Check if the character is a lowercase letter. if character.islower(): # Apply Caesar cipher transformation for lowercase letters. result += chr(((ord(character) - ord('a') + shift) % 26) + ord('a')) else: # Apply Caesar cipher transformation for uppercase letters. result += chr(((ord(character) - ord('A') + shift) % 26) + ord('A')) else: # Preserve non-alphabet characters as they are. result += character return result # Return the encrypted or decrypted result. # Prompt the user to enter the text to be encrypted text_to_encrypt = input(f"{Fore.GREEN}[?] Please Enter your text/message: ") # Prompt the user to specify the shift length (the key). key = int(input(f"{Fore.GREEN}[?] Please specify the shift length: ")) # Check if the specified key is within a valid range (0 to 25). if key > 25 or key < 0: # Display an error message if the key is out of range. print(f"{Fore.RED}[!] Your shift length should be between 0 and 25 ") sys.exit() # Exit the program if the key is invalid. # Encrypt the user's input using the specified key. encrypted_text = implement_caesar_cipher(text_to_encrypt, key) # Display the encrypted text. print(f"{Fore.GREEN}[+] {text_to_encrypt} {Fore.MAGENTA}has been encrypted as {Fore.RED}{encrypted_text}")