Arnold book cipher with python

Arnold book cipher is a method of encrypting and decrypting messages using a book as the key. In this article, we will explore different ways to implement the Arnold book cipher in Python.

Option 1: Using a Dictionary

One way to implement the Arnold book cipher is by using a dictionary to map each character in the book to a unique number. We can then use these numbers to encrypt and decrypt the message.


book = "The quick brown fox jumps over the lazy dog"
book_dict = {char: i for i, char in enumerate(book)}

def encrypt(message):
    encrypted_message = ""
    for char in message:
        if char in book_dict:
            encrypted_message += str(book_dict[char]) + " "
    return encrypted_message.strip()

def decrypt(encrypted_message):
    decrypted_message = ""
    numbers = encrypted_message.split()
    for number in numbers:
        for char, index in book_dict.items():
            if str(index) == number:
                decrypted_message += char
    return decrypted_message

To use this implementation, we first create a dictionary called book_dict where each character in the book is mapped to a unique number. The encrypt function takes a message as input and returns the encrypted message by replacing each character with its corresponding number. The decrypt function takes an encrypted message as input and returns the decrypted message by replacing each number with its corresponding character.

Option 2: Using a List

Another way to implement the Arnold book cipher is by using a list to store the characters in the book. We can then use the index of each character in the list as its corresponding number.


book = "The quick brown fox jumps over the lazy dog"
book_list = list(book)

def encrypt(message):
    encrypted_message = ""
    for char in message:
        if char in book_list:
            encrypted_message += str(book_list.index(char)) + " "
    return encrypted_message.strip()

def decrypt(encrypted_message):
    decrypted_message = ""
    numbers = encrypted_message.split()
    for number in numbers:
        decrypted_message += book_list[int(number)]
    return decrypted_message

In this implementation, we create a list called book_list where each character in the book is stored. The encrypt function replaces each character in the message with its corresponding index in the list, while the decrypt function replaces each number in the encrypted message with the character at that index in the list.

Option 3: Using ASCII Values

A third way to implement the Arnold book cipher is by using the ASCII values of the characters in the book. We can convert each character to its ASCII value and use these values as the numbers for encryption and decryption.


book = "The quick brown fox jumps over the lazy dog"

def encrypt(message):
    encrypted_message = ""
    for char in message:
        encrypted_message += str(ord(char)) + " "
    return encrypted_message.strip()

def decrypt(encrypted_message):
    decrypted_message = ""
    numbers = encrypted_message.split()
    for number in numbers:
        decrypted_message += chr(int(number))
    return decrypted_message

In this implementation, the encrypt function converts each character in the message to its ASCII value using the ord function, while the decrypt function converts each number in the encrypted message back to its corresponding character using the chr function.

After exploring these three options, the best option for implementing the Arnold book cipher in Python depends on the specific requirements of the project. If the book is relatively short and does not contain duplicate characters, option 1 using a dictionary may be the most efficient. If the book is long or contains duplicate characters, option 2 using a list may be more suitable. Option 3 using ASCII values is a more general approach that can be used with any book, but it may result in longer encrypted messages.

Ultimately, the choice between these options should be based on factors such as the size of the book, the complexity of the message, and the desired level of security.

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11 Responses

    1. Seriously? ASCII values are outdated and inefficient compared to dictionaries and lists. They are limited and cumbersome to work with. Embrace the power and flexibility of modern data structures. Dont get stuck in the Stone Age! 🙄

  1. Option 2: Using a List seems simpler, but Option 3: Using ASCII Values sounds more secure. What do you think? 🤔

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