Image Steganography.py

# Python program implementing Image Steganography

# PIL module is used to extract
# pixels of image and modify it
from PIL import Image

# Convert encoding data into 8-bit binary
# form using ASCII value of characters
def genData(data):

		# list of binary codes
		# of given data
		newd = []

		for i in data:
			newd.append(format(ord(i), '08b'))
		return newd

# Pixels are modified according to the
# 8-bit binary data and finally returned
def modPix(pix, data):

	datalist = genData(data)
	lendata = len(datalist)
	imdata = iter(pix)

	for i in range(lendata):

		# Extracting 3 pixels at a time
		pix = [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 pix[j]% 2 != 0):
				pix[j] -= 1

			elif (datalist[i][j] == '1' and pix[j] % 2 == 0):
				if(pix[j] != 0):
					pix[j] -= 1
				else:
					pix[j] += 1
				# pix[j] -= 1

		# Eighth pixel of every set tells
		# whether to stop ot read further.
		# 0 means keep reading; 1 means thec
		# message is over.
		if (i == lendata - 1):
			if (pix[-1] % 2 == 0):
				if(pix[-1] != 0):
					pix[-1] -= 1
				else:
					pix[-1] += 1

		else:
			if (pix[-1] % 2 != 0):
				pix[-1] -= 1

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

def encode_enc(newimg, data):
	w = newimg.size[0]
	(x, y) = (0, 0)

	for pixel in modPix(newimg.getdata(), data):

		# Putting modified pixels in the new image
		newimg.putpixel((x, y), pixel)
		if (x == w - 1):
			x = 0
			y += 1
		else:
			x += 1

# Encode data into image
def encode():
	img = input("\nPlease select the image in which you wish to encrypt this information : ")
	image = Image.open(img, 'r')

	data = input("\nEnter data to be encoded : ")
	if (len(data) == 0):
		raise ValueError('\nData is empty')

	newimg = image.copy()
	encode_enc(newimg, data)

	new_img_name = input("\nEnter the name of new image with extension : ")
	newimg.save(new_img_name, str(new_img_name.split(".")[1].upper()))
# Decode the data in the image
def decode():
	img = input("\nPlease select the image from which you wish to decrypt the information: ")
	image = Image.open(img, 'r')

	data = ''
	imgdata = iter(image.getdata())

	while (True):
		pixels = [value for value in imgdata.__next__()[:3] +
								imgdata.__next__()[:3] +
								imgdata.__next__()[:3]]

		# string of binary data
		binstr = ''

		for i in pixels[:8]:
			if (i % 2 == 0):
				binstr += '0'
			else:
				binstr += '1'

		data += chr(int(binstr, 2))
		if (pixels[-1] % 2 != 0):
			return data

# Main Function
def main():
    print ("\n\n\t\t\t ***** STEGANOGRAPHY PROJECT *****")
    print ("\t\t\t ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~")
    print ("\n\n Image steganograaphy is the art of encrypting messages into image files. \n This project implements the same concept.")
    print ("\n\n Please select a valid option.\n")
    print (" 1. ENCRYPT - This will hide your image in the picture you provide.")
    print (" 2. DECRYPT - This will decode the message you have encrypted in the image you provide.\n\n")
    a = int(input("\nPlease choose a valid option (1/2)\n"))
    if (a == 1):
        encode()
        print("\nCompleted !!! Your message was successfully encoded.\n")
        print("\n******************** END ********************")
    elif (a == 2):
        print("\nSuccess !!! Data found...\nDecoded Message : " + decode())
        print("\n******************** END ********************")
    else:
        raise Exception("You did not select a valid option!!! The program will now terminate! Enter correct input")

# Driver Code
if __name__ == '__main__' :

	# Calling main function
	main()