steganography.py

    import cv2
    import numpy as np
    
    
    def binary_convert(data):
        """This function converts our data into binary data."""
        if isinstance(data, str):
            return ''.join([format(ord(i), "08b") for i in data])
        elif isinstance(data, bytes) or isinstance(data, np.ndarray):
            return [format(i, "08b") for i in data]
        elif isinstance(data, int) or isinstance(data, np.uint8):
            return format(data, "08b")
        else:
            raise TypeError("This type is unsupported.")
    
    
    def encode(image_name, secret_data):
        # Reads the image
        image_rows = cv2.imread(image_name)
        # Gives us the maximum no. of bytes to encode.
        n_bytes = image_rows.shape[0] * image_rows.shape[1] * 3 // 8
        print("Maximum bytes to encode are:", n_bytes)
        if len(secret_data) > n_bytes:
            raise ValueError(
                "Insufficient bytes,we will need a bigger image or less data.")
        print("Encoding Data to Image...")
        # This adds a stopping criteria, which is used to guess the 
        secret_data += "====="
        data_index = 0
        # Converts the data to binary.
        binary_secret_data = binary_convert(secret_data)
        # Gets the size of the data to hide.
        data_len = len(binary_secret_data)
    
        for row in image_rows:
            for pixel in row:
                
                r, g, b = binary_convert(pixel)
                
                if data_index < data_len:
                    
                    pixel[0] = int(r[:-1] + binary_secret_data[data_index], 2)
                    data_index += 1
                if data_index < data_len:
                    
                    pixel[1] = int(g[:-1] + binary_secret_data[data_index], 2)
                    data_index += 1
                if data_index < data_len:
                    
                    pixel[2] = int(b[:-1] + binary_secret_data[data_index], 2)
                    data_index += 1
                
                if data_index >= data_len:
                    break
        return image_rows
    
    
    def decode(image_name):
        print("Decoding data from Image...")
        # Reading the Image
        image_rows = cv2.imread(image_name)
        binary_data = ""
        for row in image_rows:
            for pixel in row:
                r, g, b = binary_convert(pixel)
                binary_data += r[-1]
                binary_data += g[-1]
                binary_data += b[-1]
    
        # Splitting the image by 8-bits
        all_bytes = [binary_data[i: i+8] for i in range(0, len(binary_data), 8)]
        # Now, we convert the bits to characters
        decoded_data = ""
        for byte in all_bytes:
            decoded_data += chr(int(byte, 2))
            if decoded_data[-5:] == "=====":
                break
        return decoded_data[:-5]
    
    # We will assign variables as the name of the input and the output file.
    input_img = "img.png" # Enter the name of your image here.
    out_img = "img_out.png" # Also, update this accordingly.
    
    # Now we can just call the encode() function to encode the image and save the data to a variable.
    enc_image = encode(input_img, "Hi Folks!") # Replace "Hi Folks!" with the data you want to encode.
    cv2.imwrite(out_img, enc_image) #Using OpenCV to write the result to an actual image file.
    
    # We can decode the image by simply calling the decode() function.
    decode(out_img)