Image Steganography using python

steganography.py

#we have to import Image from PIL library, as I sadi earlier PIL used to extract the details of image, 
#specially pixels of image
from PIL import Image 


def genrateData(payload_data): 
		
		newData = [] 
		
		for i in payload_data: 
			newData.append(format(ord(i), '08b')) 
		return newData 
		
# Pixels are modified according to the 
# 8-bit binary payload_data and finally returned 
def modPix(pixel, payload_data): 
	
	datalist = genrateData(payload_data) 
	lendata = len(datalist) 
	imdata = iter(pixel) 

	for i in range(lendata): 
		
		# Extracting 3 pixelels at a time 
		pixel = [value for value in imdata.__next__()[:3] +
								imdata.__next__()[:3] +
								imdata.__next__()[:3]] 
									
		# Pixel value should be made 
		# odd for 1 and even for 0 
		for j in range(0, 8): 
			if (datalist[i][j]=='0') and (pixel[j]% 2 != 0): 
				
				if (pixel[j]% 2 != 0): 
					pixel[j] -= 1
					
			elif (datalist[i][j] == '1') and (pixel[j] % 2 == 0): 
				pixel[j] -= 1
				
		# Eigh^th pixel of every set tells 
		# whether to stop ot read further. 
		# 0 means keep reading; 1 means the 
		# message is over. 
		if (i == lendata - 1): 
			if (pixel[-1] % 2 == 0): 
				pixel[-1] -= 1
		else: 
			if (pixel[-1] % 2 != 0): 
				pixel[-1] -= 1

		pixel = tuple(pixel) 
		yield pixel[0:3] 
		yield pixel[3:6] 
		yield pixel[6:9] 

def encode_enc(newImage, payload_data): 
	w = newImage.size[0] 
	(x, y) = (0, 0) 
	
	for pixel in modPix(newImage.getdata(), payload_data): 
		
		# Putting modified pixels in the new image 
		newImage.putpixel((x, y), pixel) 
		if (x == w - 1): 
			x = 0
			y += 1
		else: 
			x += 1
			
# Encode data into image 
def encode(): 
	img = input("Enter the image name(Eg: A.png) ") 
	image = Image.open(img, 'r') 
	
	payload_data = input("Enter Your Message ") 
	if (len(payload_data) == 0): 
		raise ValueError('Please type your Message') 
		
	newImage = image.copy() 
	encode_enc(newImage, payload_data) 
	
	new_img_name = input("Enter the name of new image(with extension): ") 
	newImage.save(new_img_name, str(new_img_name.split(".")[1].upper())) 

# Decode the payload_data in the image 
def decode(): 
	img = input("Enter image name to decode (b.png):") 
	image = Image.open(img, 'r') 
	
	payload_data = '' 
	secretData = iter(image.getdata()) 
	
	while (True): 
		pixels = [value for value in secretData.__next__()[:3] +
								secretData.__next__()[:3] +
								secretData.__next__()[:3]] 
		# string of binary payload_data 
		binstr = '' 
		
		for i in pixels[:8]: 
			if (i % 2 == 0): 
				binstr += '0'
			else: 
				binstr += '1'
				
		payload_data += chr(int(binstr, 2)) 
		if (pixels[-1] % 2 != 0): 
			return payload_data 
			
# Main Function		 
def main(): 
	a = int(input(":: Image Steganography::\n"
						"Choose \n 1. Encoding \n 2. Decoding\n")) 
	if (a == 1): 
		encode() 
		
	elif (a == 2): 
		print("Decoded succesfully- " + decode()) 
	else: 
		raise Exception("Please try again") 
		
# Driver Code 
if __name__ == '__main__' : 
	
	# Calling main function 
	main()