main_file.py

from rcncipher import encrypt, decrypt
from datetime import datetime


def text_to_128_bit_hex_chunks(text):
    # Convert text to bytes
    text_bytes = text.encode('utf-8')

    # Calculate the number of 128-bit chunks
    num_chunks = (len(text_bytes) + 15) // 16

    # Pad the text_bytes to make its length a multiple of 16 bytes
    padded_bytes = text_bytes.ljust(num_chunks * 16, b'\0')

    # Divide the padded bytes into 128-bit chunks
    chunks = [padded_bytes[i:i+16] for i in range(0, len(padded_bytes), 16)]

    # Convert each chunk to hexadecimal representation
    hex_chunks = [chunk.hex() for chunk in chunks]
    # print(hex_chunks)
    return hex_chunks

def text_to_hex(text):
    # Convert text to bytes
    text_bytes = text.encode('utf-8')

    # Convert bytes to hexadecimal representation
    hex_representation = text_bytes.hex()

    return hex_representation

def hex_to_text(hex_string):
    # Convert hexadecimal string to bytes
    byte_string = bytes.fromhex(hex_string)

    # Decode bytes to text using UTF-8 encoding
    text = byte_string.decode('utf-8')

    return text

def read_file(file_path):
    try:
        with open(file_path, 'r', encoding='utf-8') as file:
            content = file.read()
        return content
    except FileNotFoundError:
        print(f"File '{file_path}' not found.")
        return None
    except Exception as e:
        print(f"Error reading file '{file_path}': {e}")
        return None

def write_to_file(file_path, content):
    try:
        with open(file_path, 'w', encoding='utf-8') as file:
            file.write(content)
        print(f"Content successfully written to '{file_path}'.")
    except Exception as e:
        print(f"Error writing to file '{file_path}': {e}")

# User input to perform encryption or decryption

while(True):
    choice = input("Enter 'e' for encryption or 'd' for decryption: ")

    if choice == 'e':
        # Get the key and plaintext from the user
        key = text_to_hex(input("Enter the key: "))
        path = input("Enter the file name to encrypt (text file): ")

        plaintext = read_file(path)

        # Convert the plaintext into 128-bit chunks
        chunks = text_to_128_bit_hex_chunks(plaintext)
        # Encrypt each 128-bit chunk
        ciphertext = ''.join(encrypt(chunk, key) for chunk in chunks)

        #write to file
        #save file to encrypted-time-date.txt
        #include date time string in path
        current_datetime = datetime.now()

        # Format the date and time as a string
        datetime_string = current_datetime.strftime("%Y-%m-%d-%H-%M-%S")

        write_to_file(f"encrypted--{datetime_string}-{path}", ciphertext)

        # print("Ciphertext:", ciphertext)
        # break
    elif choice == 'd':
        # Get the key and ciphertext from the user
        key = text_to_hex(input("Enter the key: "))
        if len(key) <= 32:  # Each hexadecimal character represents 4 bits
            print("Hexadecimal representation:", key)
        else:
            raise ValueError("Hexadecimal representation exceeds 128 bits.")
        path = input("Enter the file name to decrypt (text file)")

        ciphertext = read_file(path)

        # Decrypt the ciphertext
        decrypted_chunks = [hex_to_text(decrypt(ciphertext[i:i+32], key)) for i in range(0, len(ciphertext), 32)]

        # Remove the padding and convert the decrypted chunks to text
        decrypted_text = ''.join(decrypted_chunks)

        # print("Decrypted text:", decrypted_text)
        #save file to decrypted-time-date.txt
        #include date time string in path
        current_datetime = datetime.now()

        # Format the date and time as a string
        datetime_string = current_datetime.strftime("%Y-%m-%d-%H-%M-%S")
        write_to_file(f"decrypted--{datetime_string}-{path}", decrypted_text)
    elif choice == 'exit':	
        break
    else:
        choice = input("Invalid choice. Type exit to, well, exit. Enter 'e' for encryption or 'd' for decryption: ")
        continue