ImageSteg.py

from PIL import Image
import pandas as pd
import numpy as np

def msgtobinary(msg):
    if type(msg) == str:
        result = ''.join([format(ord(i), "08b") for i in msg])
    elif type(msg) == bytes or type(msg) == np.ndarray:
        result = [format(i, "08b") for i in msg]
    elif type(msg) == int or type(msg) == np.uint8:
        result = format(msg, "08b")
    else:
        raise TypeError("Input type is not supported in this function")
    return result

class ImageSteg:

    def __fillMSB(self, inp):
        '''
        0b01100 -> [0,0,0,0,1,1,0,0]
        '''
        inp = inp.split("b")[-1]
        inp = '0' * (7 - len(inp)) + inp
        return [int(x) for x in inp]

    def __decrypt_pixels(self, pixels):
        '''
        Given list of 7 pixel values -> Determine 0/1 -> Join 7 0/1s to form binary -> integer -> character
        '''

        pixels = [str(x % 2) for x in pixels]
        bin_repr = "".join(pixels)
        return chr(int(bin_repr, 2))

    def encrypt_text_in_image(self, image_path, msg, target_path=""):
        img = np.array(Image.open(image_path))
        imgArr = img.flatten()
        msg += "<-END->"
        msgArr = [self.__fillMSB(bin(ord(ch))) for ch in msg]
        idx = 0
        for char in msgArr:
            for bit in char:
                if bit == 1:
                    if imgArr[idx] == 0:
                        imgArr[idx] = 1
                    else:
                        imgArr[idx] = imgArr[idx] if imgArr[idx] % 2 == 1 else imgArr[idx] - 1
                else:
                    if imgArr[idx] == 255:
                        imgArr[idx] = 254
                    else:
                        imgArr[idx] = imgArr[idx] if imgArr[idx] % 2 == 0 else imgArr[idx] + 1
                idx += 1
        savePath=target_path+target_path.split("/")[0]+".png"
        resImg = Image.fromarray(np.reshape(imgArr, img.shape))
        resImg.save(savePath)
        return

    def decrypt_text_in_image(self, image_path, target_path=""):
        '''
        Read image -> Extract Text -> Return
        '''
        img = np.array(Image.open(image_path))

        imgArr = np.array(img).flatten()

        decrypted_message = ""
        for i in range(7, len(imgArr), 7):
            decrypted_char = self.__decrypt_pixels(imgArr[i - 7:i])
            decrypted_message += decrypted_char

            if len(decrypted_message) > 10 and decrypted_message[-7:] == "<-END->":
                break

        return decrypted_message[:-7]



        if (len(msg) == 0):
            raise ValueError('Data entered to be encoded is empty')
        no_of_bytes = (img.shape[0] * img.shape[1] * 3) // 8
        print("\t\nMaximum bytes to encode in Image :", no_of_bytes)
        if (len(msg) > no_of_bytes):
            raise ValueError("Insufficient bytes Error, Need Bigger Image or give Less Data !!")
        binary_data = msgtobinary(msg)
        print("\n")
        length_data = len(binary_data)
        print("\nThe Length of Binary data", length_data)