task6.py

import random

from PIL import Image, ImageDraw
from bitarray._bitarray import bitarray
from bitarray.util import int2ba

text = b'Very very secret text'
lamb = 0.7
sigma = 3
K0 = 42

image = Image.open("temp.jpg")
draw = ImageDraw.Draw(image)
width = image.size[0]
height = image.size[1]
pix = image.load()

bit_chars = []
for char in text:
    bites = [1 if i else 0 for i in int2ba(char)]
    bit_chars.append(([0] * (8 - len(bites)) + bites))

random.seed(K0)

for i in range(len(bit_chars)):
    for j in range(len(bit_chars[i])):
        count = i * len(bit_chars) + j

        x = random.uniform(sigma, width - sigma)
        y = random.uniform(sigma, height - sigma)

        r = pix[x, y][0]
        g = pix[x, y][1]
        b = pix[x, y][2]
        power = 0.3 * r + 0.59 * g + 0.11 * b

        b += int((2 * bit_chars[i][j] - 1) * lamb * power)

        if b < 0:
            b = 0
        if b > 255:
            b = 255
        draw.point((x, y), (r, g, b))


image.save("temp_with_secret.png", "PNG")

print('Скрытие информации завершено')

image = Image.open("temp_with_secret.png")
pix = image.load()
random.seed(K0)

width = image.size[0]
height = image.size[1]
res = bitarray()
for i in range(sigma, width - sigma):
    for j in range(sigma, height - sigma):
        x = random.uniform(sigma, width - sigma)
        y = random.uniform(sigma, height - sigma)

        temp_b = 0
        b = pix[x, y][2]
        for k in range(1, sigma + 1):
            bt = pix[x, y + k][2]
            bd = pix[x, y - k][2]
            bl = pix[x - k, y][2]
            br = pix[x, y + k][2]
            temp_b += bt + bd + bl + br
        temp_b /= 4 * sigma

        res += [temp_b < b]

print(res.tobytes()[:len(text)])