assignment3.py

from Crypto.Cipher import DES
from Crypto import Random
from PIL import Image


def get_iv():
	return Random.new().read(DES.block_size)


def encrypt_image(path, path_out, cipher):
	with open(path, "rb") as f:
		image = f.read()
	header, image = image[:64], image[64:]
	image, ign = image[:(len(image) // 8) * 8], image[(len(image) // 8) * 8:]
	encrypted_image = cipher.encrypt(image)
	encrypted_image = encrypted_image + ign
	encrypted_image = header + encrypted_image
	with open(path_out, "wb") as f:
		f.write(encrypted_image)


if __name__ == '__main__':
	path = input()
	if path.endswith('.png') or path.endswith('.jpg'):
		image = Image.open(path)
		imag = image.convert('L').point(lambda x: 255 if x > 128 else 0, mode='1')
		imag.save(path[:-4] + '.bmp')
	key = bytes(input()[:8], 'ascii')
	cipher_ecb = DES.new(key, mode=DES.MODE_ECB)
	cipher_cbc = DES.new(key, DES.MODE_CBC, get_iv())
	encrypt_image(path[:-4] + '.bmp', path[:-4] + '_ecb' + '.bmp', cipher_ecb)
	encrypt_image(path[:-4] + '.bmp', path[:-4] + '_cbc' + '.bmp', cipher_cbc)