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import gmpy2
from secret import flag
from Crypto.Util.number import *

f = bytes_to_long(flag)
p = getPrime(512)
g = getPrime(128)
h = gmpy2.invert(f+20192020202120222023, p) * g % p

print('h =', h)
print('p =', p)

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import matplotlib.pyplot as plt
import cv2
import numpy as np
from PIL import Image
def arnold_encode(image, shuffle_times, a, b):
    """ Arnold shuffle for rgb image
    Args:
        image: input original rgb image
        shuffle_times: how many times to shuffle
    Returns:
        Arnold encode image
    """
    arnold_image = np.zeros(shape=image.shape)

    h, w = image.shape[0], image.shape[1]
    N = h

    for time in range(shuffle_times):
        for ori_x in range(h):
            for ori_y in range(w):

                new_x = (1*ori_x + b*ori_y)% N
                new_y = (a*ori_x + (a*b+1)*ori_y) % N

                arnold_image[new_x, new_y, :] = image[ori_x, ori_y, :]

        image = np.copy(arnold_image)

    cv2.imwrite('en_flag.png', arnold_image, [int(cv2.IMWRITE_PNG_COMPRESSION), 0])
    return arnold_image

img = cv2.imread('coke.png')
arnold_encode(img,6,9,1)