image steganography

img_steganography.py

import argparse

from PIL import Image

def embed_message(image_path, message, output_path):
    org_img = Image.open(image_path)
    org_pixelMap = org_img.load()

    enc_img = Image.new(org_img.mode, org_img.size)
    enc_pixelsMap = enc_img.load()

    binary_msg = ''.join(format(ord(char), '08b') for char in message)
    msg_len = len(binary_msg)
    msg_index = 0

    for row in range(org_img.size[0]):
        for col in range(org_img.size[1]):
            r, g, b = org_pixelMap[row, col]

            if row == 0 and col == 0:
                msg_len_bin = format(msg_len, '024b')
                r = int(msg_len_bin[:8], 2)
                g = int(msg_len_bin[8:16], 2)
                b = int(msg_len_bin[16:], 2)
                enc_pixelsMap[row, col] = (r, g, b)
            elif msg_index < msg_len:
                r_bin = format(r, '08b')
                g_bin = format(g, '08b')
                b_bin = format(b, '08b')

                new_r_bin = r_bin[:-1] + binary_msg[msg_index]
                new_r = int(new_r_bin, 2)
                msg_index += 1

                if msg_index < msg_len:
                    new_g_bin = g_bin[:-1] + binary_msg[msg_index]
                    new_g = int(new_g_bin, 2)
                    msg_index += 1
                else:
                    new_g = g

                if msg_index < msg_len:
                    new_b_bin = b_bin[:-1] + binary_msg[msg_index]
                    new_b = int(new_b_bin, 2)
                    msg_index += 1
                else:
                    new_b = b

                enc_pixelsMap[row, col] = (new_r, new_g, new_b)
            else:
                enc_pixelsMap[row, col] = (r, g, b)

    org_img.close()

    enc_img.save(output_path)
    enc_img.close()
    print(f"Message embedded successfully. Encrypted image saved as {output_path}")

def extract_message(image_path):
    enc_img = Image.open(image_path)
    enc_pixelMap = enc_img.load()

    binary_msg = ""
    msg_len = 0

    for row in range(enc_img.size[0]):
        for col in range(enc_img.size[1]):
            r, g, b = enc_pixelMap[row, col]

            if row == 0 and col == 0:
                msg_len = (r << 16) | (g << 8) | b
            elif msg_len > 0:
                r_bin = format(r, '08b')
                g_bin = format(g, '08b')
                b_bin = format(b, '08b')

                binary_msg += r_bin[-1]
                msg_len -= 1

                if msg_len > 0:
                    binary_msg += g_bin[-1]
                    msg_len -= 1

                if msg_len > 0:
                    binary_msg += b_bin[-1]
                    msg_len -= 1

    message = ''.join(chr(int(binary_msg[i:i+8], 2)) for i in range(0, len(binary_msg), 8))
    enc_img.close()
    return message

def main():
    parser = argparse.ArgumentParser(description="Steganography tool to hide and extract messages in images.")
    subparsers = parser.add_subparsers(dest="command", required=True, help="Sub-command to run.")

    # Subparser for the "hide" command
    hide_parser = subparsers.add_parser("hide", help="Hide a message in an image.")
    hide_parser.add_argument("-p", "--image", required=True, help="Path to the image file.")
    hide_parser.add_argument("-f", "--file", required=True, help="Path to the file containing the secret message.")
    hide_parser.add_argument("-o", "--output", required=True, help="Path to the output image file.")

    # Subparser for the "extract" command
    extract_parser = subparsers.add_parser("extract", help="Extract a message from an image.")
    extract_parser.add_argument("-u", "--image", required=True, help="Path to the image file containing the hidden message.")
    extract_parser.add_argument("-o", "--output", required=True, help="Path to the output file for the extracted message.")

    args = parser.parse_args()

    if args.command == "hide":
        with open(args.file, "r") as f:
            message = f.read()
        embed_message(args.image, message, args.output)
    elif args.command == "extract":
        hidden_message = extract_message(args.image)
        with open(args.output, "w") as f:
            f.write(hidden_message)
        print(f"Message extracted successfully. Saved to {args.output}")

if __name__ == "__main__":
    main()