simple_music_cipher_crude_brute

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# Filename: simple_music_cipher.py
# Author: Jeoi Reqi
# Original Key File:   https://pastebin.com/sHMQDfhM

"""
!!NOTICE!!

THIS IS A CRUDE BRUTE FORCE DECODER AND IS HIGHLY
LIMITED IN FUNCTIONALITY & INPUT LENGTHS. THIS WILL
MOST LIKELY GIVE BAD RESULTS UNLESS COMMON WORDS OF
SHORT LENGTHS. I WILL BE UPDATING THIS SCRIPT SHORTLY.
ANY ADVICE TO HOW TO PROPERLY DECODE A STRING USING
A KEY WHERE MULTIPLE VALUES ARE GIVEN FOR EACH LETTER.
NEXT ATTEMPT WILL INVOLVE INDEXING THE KEY VALUES AND
THEN CYCLING THEM RECURSIVELY AND OUTPUT ALL VARIABLE
POSSIBILITIES TO THE TERMINAL FOR THE USER TO SELECT.


This script demonstrates a simple music cipher, allowing users to encode and decode a short message using a specified key for notes A-G.
The decoding utilizes the NLTK words dataset and brute force methods to generate possible decodings.

Requirements:
- Python 3
- NLTK (Natural Language Toolkit) library: Install it using 'pip install nltk'
- NLTK words dataset: If not present, uncomment 'nltk.download('words')' and run the script. Comment it out once downloaded.

Encoding Example:
    message_to_encode = "hello world"  #Short strings w/ common words work the best in this version.
    encoded_message = encode(message_to_encode)
    print(f"Encoded: {encoded_message}")

Decoding Example:
    print("Possible Decodings:")
    decode(encoded_message)

Usage:
1. Run the script and enter the message to encode.
2. The encoded message will be displayed, and possible decodings will be generated.
3. Optionally, save the decoding results to a file.

Note: Numbers in the message are ignored during encoding and decoding.

For more information on the cipher and its cryptanalysis, refer to the references included in the script.

"""

import nltk
import os

# Uncomment the line below if NLTK words dataset is not present on your system
# nltk.download('words')

def encode(message):
    key = {
        'a': 'a', 'b': 'b', 'c': 'c',
        'd': 'd', 'e': 'e', 'f': 'f',
        'g': 'g', 'h': 'a', 'i': 'b',
        'j': 'c', 'k': 'd', 'l': 'e',
        'm': 'f', 'n': 'g', 'o': 'a',
        'p': 'b', 'q': 'c', 'r': 'd',
        's': 'e', 't': 'f', 'u': 'g',
        'v': 'a', 'w': 'b', 'x': 'c',
        'y': 'd', 'z': 'e',
        ' ': ' '  # add space character to the key
    }

    encoded_message = ''.join([key.get(char.lower(), char) if char.isalpha() else char for char in message])
    return encoded_message

def decode(encoded_message):
    reverse_key = {
        'a': 'ahov', 'b': 'bipw', 'c': 'cjqx',
        'd': 'dkry', 'e': 'elsz', 'f': 'fmt',
        'g': 'gnu'
    }

    english_words = set(nltk.corpus.words.words())

    def generate_possible_decodings(decoded_prefix, remaining_encoded, all_combinations):
        if not remaining_encoded:
            if decoded_prefix.lower() in english_words:
                all_combinations.append(decoded_prefix.strip())
            return

        current_char = remaining_encoded[0]
        possibilities = reverse_key.get(current_char, [current_char])

        for possibility in possibilities:
            new_decoded_prefix = decoded_prefix + possibility
            generate_possible_decodings(new_decoded_prefix, remaining_encoded[1:], all_combinations)

    def decode_message(remaining_words, decoded_sentence, all_combinations):
        if not remaining_words:
            all_combinations.append(decoded_sentence.strip())
            return

        current_word = remaining_words[0]
        word_combinations = []

        generate_possible_decodings('', current_word, word_combinations)

        for word_combination in word_combinations:
            new_decoded_sentence = decoded_sentence + word_combination + ' '
            decode_message(remaining_words[1:], new_decoded_sentence, all_combinations)

    def print_combinations(combinations):
        for combination in combinations:
            print(f"\t\t{combination}")

    words = encoded_message.split()
    all_combinations = []

    decode_message(words, '', all_combinations)
    print_combinations(all_combinations)

    return all_combinations

def save_to_file(combinations):
    filename = 'decoding_results.txt'
    with open(filename, 'w') as file:
        for combination in combinations:
            file.write(f"{combination}\n")
    print(f"Results saved to {filename}")

# Example usage:
print("\n:: [SIMPLE MUSIC ENCODER/DECODER] ::\n\n")
user_message = input("\tEnter the message to encode: ")
encoded_message = encode(user_message)
print(f"\n\tEncoded: {encoded_message}\n")

print("\nPossible Decodings:\n")
decoded_combinations = decode(encoded_message)

save_option = input("\nDo you want to save the decoding results to a file?\n\n1: Yes\n2: No\n\nWhat is your choice (1 Or 2?) ")
if save_option == '1':
    save_to_file(decoded_combinations)
else:
    print("\nProgram Ending. Thank you!\n")